PlungeBox XL: Lay-Flat Cold Tub

Name: PlungeBox XL: Lay-Flat Cold Tub
Brand: SAUNABOX
SKU: PLUNGBX-XL
Price: 249.0 USD
Availability: InStock

by SAUNABOX

Save 38%

$399.00

$399.00 - $399.00

$399.00

$249.00

$249.00 - $249.00

$249.00

✓ Authorized SAUNABOX Dealer
✓ Lowest Price Guaranteed
✓ FREE & FAST Shipping: In Stock and Ready to Ship
✓ Questions? Call an RFA Team Member: 1-855-864-6442

Description

Lay-Flat Cold Tub

Full-Body Cold Immersion. Actually Full-Body.

Most cold plunge tubs are designed for seated immersion — you lower yourself in and sit upright, knees bent, water reaching your chest. That works. But the PlungeBox XL: Lay-Flat Cold Tub takes a different approach. Its wide oval footprint — 48.4" long × 31.1" wide — lets you lie down and immerse completely, from shoulders to feet, in a single continuous position. For tall athletes, that's not a luxury. It's the difference between a useful tool and one that doesn't cover your legs.

At a capacity of 500 liters, the XL holds enough water to fully submerge at lay-flat depth. The extra thick insulation maintains cold temperatures for extended periods between ice additions or chiller cycles — you're not racing against the clock to finish before the water warms. At just 5.7kg when empty, it sets up quickly, deflates for storage, and travels easily.

The XL is designed for athletes up to 6'6" and 350 lbs — proportioned so that size isn't an obstacle to a complete cold therapy session. Pair it with the PlungeBox 1/2HP Water Chiller Pro and the ice question goes away entirely: consistent temperature, on schedule, every time.

PlungeBox XL Lay-Flat Cold Tub showing full oval shape and lay-flat immersion design

Design & Construction

Four Design Decisions That Make the XL Different

The PlungeBox XL isn't a stretched version of a standard tub. The oval lay-flat shape, insulation spec, and weight were each deliberate choices built around full-body cold therapy.

🛁

Oval Lay-Flat Design

The oval shape is wider than rectangular alternatives and longer than barrel-style plunges — designed specifically for lying down rather than sitting upright. At 48.4" long and 31.1" wide with a 29.5" depth, users up to 6'6" can submerge from shoulders to feet in a single comfortable position, with room to relax rather than contort.

48.4" L × 31.1" W × 29.5" H · LAY-FLAT

🧊

500L Capacity With Superior Insulation

500 liters provides enough water volume for complete submersion at lay-flat depth. Extra thick insulation on the tub walls retains cold temperature for extended periods — significantly reducing how often you need to add ice during a session and between sessions. Less ice management, more cold therapy.

500L CAPACITY · EXTRA THICK INSULATION

🎒

5.7kg — Genuinely Portable

At just 5.7 kilograms empty, the XL is light enough to carry, store flat, and move between locations. The included carrying case makes transport straightforward. Use it at home, at a facility, or outdoors — it sets up wherever you need it. Most hard-shell cold plunge tubs of comparable size weigh 10–20× more.

5.7KG EMPTY · CARRYING CASE INCLUDED

🔌

Chiller-Ready

The PlungeBox XL is designed to pair with the PlungeBox 1/2HP Water Chiller Pro for temperature-controlled sessions without ice. The tub's port connection accommodates the chiller hose set for continuous cooling and filtration. No ice, no temperature drift, no scheduling around cooldown times — just consistent cold on demand.

COMPATIBLE WITH PLUNGEBOX CHILLER PRO

Why Cold Therapy

Eight Reasons Serious Athletes Make Cold Plunging a Daily Practice

Cold water immersion has one of the strongest evidence bases in sports recovery. The XL's lay-flat design means your legs, hips, and lower back — the largest muscle groups — are fully submerged rather than partially exposed.

Muscle Recovery

Reduce Inflammation

Boost Circulation

Energy & Mood

Mental Resilience

Sleep Performance

Reduce Soreness

Stress Reduction

Feature Deep-Dives

Built for Athletes Who Take Cold Therapy Seriously

The PlungeBox XL gets the details right — from the insulation that keeps water cold longer, to the insulated cover lid that preserves temperature between sessions.

PlungeBox XL Lay-Flat Cold Tub showing athlete lying flat inside oval tub for full-body immersion

Lay-Flat Immersion

Your Legs Deserve Cold Therapy Too.

In a standard barrel or upright plunge tub, you're seated with your knees bent — which means your legs are partially out of the water and your hips and lower back are compressed. The XL's oval lay-flat shape changes the geometry entirely. Lie back, extend fully, and submerge your entire body from shoulders to feet at one consistent depth. That's the point of cold immersion — getting as much surface area into cold water as possible, all at once.

48.4" long — full extension for users up to 6'6"
31.1" wide oval shape — comfortable lay-flat position without contortion
29.5" depth — sufficient for full-body submersion lying flat
Designed for athletes up to 6'6" / 350 lbs

Fits to 6'6" / 350 lbs Full-Body Submersion Oval Design

PlungeBox XL with insulated cover lid on showing thick wall construction and insulation

Superior Insulation

Stays Cold Longer. Needs Less Ice.

Thin tub walls bleed temperature fast — you end up adding ice mid-session or watching your session get warmer by the minute. The XL's extra thick insulation retains cold temperatures for extended periods. The included insulated cover lid keeps the water cold between sessions so your next plunge doesn't require a full ice reset. With the PlungeBox Chiller Pro, the insulation's job is maintenance — the chiller handles the cooling and the walls hold it there.

Extra thick insulation retains cold temperature longer than standard tubs
Insulated cover lid included — preserves temperature between sessions
Reduces ice consumption over time
Compatible with PlungeBox 1/2HP Chiller Pro for ice-free operation

Extra Thick Insulation Insulated Lid Included Chiller Compatible

PlungeBox XL deflated and packed in carrying case showing compact storage form

Portable by Design

A Cold Plunge Tub That Weighs Less Than Your Gym Bag.

At 5.7kg empty, the PlungeBox XL is lighter than most comparable cold plunge tubs by an order of magnitude. A 500-liter hard-shell tub at this size would weigh 40–80kg on its own. The XL inflates to full size using the included hand pump, and deflates flat for the carrying case when you're done. Home use, gym use, outdoor use — it goes where you go.

5.7kg empty — carries in one hand
Inflates with the included hand pump, no electric pump required
Deflates flat for compact storage and transport
Carrying case included for clean, organized storage

5.7kg Empty Hand Pump Included Carrying Case

PlungeBox XL drainage hose being used to empty the tub after a cold plunge session

Easy Maintenance

Water Change in Minutes. No Tools, No Hassle.

The included drainage hose makes emptying the tub straightforward — route it to a drain or outdoors and let it flow. PlungeBox recommends changing the water every two weeks depending on usage frequency. Between changes, wipe down the interior with a natural cleaning spray, rinse, and dry. That's the full maintenance routine. No special chemicals, no filter media to replace, no complicated cleaning systems.

Drainage hose included — empties without lifting or tipping the tub
Water change recommended every 2 weeks based on use frequency
Clean with natural spray, rinse, and dry — no chemicals required
2-year warranty for peace of mind

Drainage Hose Included 2-Year Warranty Simple Maintenance

Technical Specifications

PlungeBox XL: Lay-Flat Cold Tub — Full Specs

Complete dimensions, capacity, and compatibility information.

In The Box

Everything You Need to Start Your First Session

The PlungeBox XL ships complete with all setup and maintenance accessories.

🛁

PlungeBox XL Tub

The oval lay-flat tub — 123cm × 79cm × 75cm, 500L capacity, extra thick insulation

🧊

Insulated Cover Lid

Keeps water cold between sessions and reduces evaporation — extends your ice or chiller efficiency

🎒

Carrying Case

Compact case for the deflated tub — keeps everything organized for storage or transport

💨

Hand Pump

Manual inflation pump — inflates the tub to full size, no electric pump or power source required

🚿

Drainage Hose

Routes water to a drain or outdoor area for easy, clean emptying without tipping the tub

🛡️

2-Year Warranty

2-year limited warranty covering manufacturing defects under normal use conditions

Setup Guide

Inflate, Fill, and Plunge.

Unpack and Position the Tub

Remove the PlungeBox XL from its carrying case and place it on a flat, stable surface near a water source. Indoors or outdoors both work — choose a location where drainage will be convenient when you're ready to empty.

Inflate with the Hand Pump

Use the included hand pump to inflate the tub walls to full rigidity. The XL requires firm inflation for structural integrity at full water capacity. Check all valves are sealed securely before filling.

Fill with Cold Water

Fill the tub with cold water to your desired session depth. For ice-only sessions, fill to just below the level where you'll lie and add ice to reach your target temperature. For chiller sessions, fill completely and let the chiller handle the cooling.

Add Ice or Connect the Chiller

For ice sessions: add ice and wait 10–15 minutes for temperature to equalize before entering. For chiller sessions: connect the PlungeBox 1/2HP Chiller Pro hose set and set your target temperature via the app.

Plunge, Recover, Drain

Enter the tub and lie flat for full-body immersion. After your session, use the drainage hose to empty the tub. Place the insulated lid on before the next session to preserve temperature. Change the water every two weeks based on use frequency.

PlungeBox XL fully inflated and filled showing lay-flat immersion setup

Designed For

Taller Athletes. Serious Plungers. Full Recovery.

The XL was designed around the users that standard cold plunge tubs fail — and the use cases that upright tubs can't fully serve.

🏋️

Athletes 6'0" – 6'6"

Standard plunge tubs leave taller athletes with legs above the water line. The XL's 48.4" length and lay-flat shape accommodates full-length submersion for users up to 6'6". Your quads, hamstrings, and calves — the muscles that take the most volume load — are fully immersed, not hovering above the waterline.

🧊

Lay-Flat Recovery Protocol

Lying flat in cold water changes the physiological experience. Your entire posterior chain — glutes, hamstrings, lower back — is submerged simultaneously. The mental component of lying flat is also different from sitting upright: a more complete surrender to the cold that many experienced plungers prefer for recovery protocols.

💳

HSA/FSA Eligible

The PlungeBox XL may qualify for HSA/FSA purchase through Truemed for customers with qualifying medical conditions. Cold water immersion therapy has documented medical and rehabilitative applications supporting potential eligibility. Eligible customers typically save 25–35% using pre-tax health dollars.

Common Questions

Frequently Asked Questions

Everything you need to decide if the PlungeBox XL is right for your practice.

The PlungeBox XL is a lay-flat tub — its oval shape (48.4" × 31.1") is designed for lying down rather than sitting upright. Standard barrel or upright plunge tubs have you seated with bent knees, which leaves your legs partially above the water line. The XL lets you submerge fully from shoulders to feet lying flat, with a 500L capacity to support that immersion depth. It also accommodates users up to 6'6" and 350 lbs where most upright tubs are limiting for taller athletes.

Length: 123cm (48.4") — Width: 79cm (31.1") — Height/Depth: 75cm (29.5") — Capacity: 500 liters. The tub weighs 5.7kg empty. It fits users up to 6'6" (198cm) and 350 lbs (159kg) comfortably in a lay-flat position.

Yes — the PlungeBox XL is compatible with the PlungeBox 1/2HP Water Chiller Pro. The chiller connects via the tub's hose port using the hose set included with the chiller. With the chiller attached, your water reaches and holds your target temperature continuously — no ice required. The chiller also includes built-in 20-micron filtration and ozone sanitation, which is particularly useful for a 500L tub where manual water management is more effort.

The XL's extra thick tub walls reduce heat transfer between the cold water and the surrounding environment. Combined with the included insulated cover lid, the tub retains cold temperature significantly longer than standard thin-wall inflatable tubs. Actual retention time depends on ambient temperature, starting water temperature, and whether you're using ice or a chiller. In warmer ambient conditions you'll need more ice or a chiller to maintain temperature; in cooler environments, the insulation alone provides meaningful retention between sessions.

Fill via a standard garden hose or other water source — at typical household flow rates, filling to session depth takes 10–20 minutes depending on how full you fill it. Drain using the included drainage hose, which routes water to a floor drain, outdoor area, or anywhere gravity will carry it. You don't need to tip or lift the tub to drain it. A full 500L drain takes 20–40 minutes via gravity depending on hose routing and elevation differential.

PlungeBox recommends changing the water every two weeks, adjusted based on how frequently you use the tub. Higher frequency use warrants more frequent changes. Between changes, wipe down the interior with a natural cleaning spray, rinse, and dry. If you're using the PlungeBox Chiller Pro, its built-in ozone sanitation and 20-micron filtration will extend time between full water changes by keeping the water cleaner continuously.

The PlungeBox XL includes a hand pump — no electric pump or power source is required. Manual inflation of a 500L tub takes approximately 5–10 minutes depending on effort. The tub should be inflated firmly (not soft) before filling, as the water weight is significant and proper inflation provides the structural integrity needed. Deflation takes 2–3 minutes once water is drained and valves are opened.

Yes — the PlungeBox XL is suitable for indoor and outdoor use. Outdoor use works well in cooler ambient temperatures where the environment helps maintain water cold. In warmer outdoor conditions, the insulation still provides thermal retention but you'll use more ice or rely more heavily on a chiller to maintain target temperature. The tub material is durable for regular outdoor exposure.

The PlungeBox XL may qualify for HSA/FSA purchase through Truemed for customers with qualifying medical conditions. Cold water immersion therapy has documented applications in sports medicine, post-surgical recovery, and inflammation management. Eligible customers typically save 25–35% using pre-tax health account dollars. Eligibility is confirmed through Truemed's qualification process at checkout.

The PlungeBox XL includes a 2-Year Limited Warranty covering manufacturing defects in materials and workmanship under normal use conditions. This includes the tub, insulated cover lid, and included accessories. Contact PlungeBox customer support with your order confirmation to initiate a warranty claim.