Underlay TT

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Clean the Underlay after each use. Wash it in warm water below 40°C (104°F) using a mild, pH-balanced detergent that is free of fragrance, bleach, and dye. Rinse thoroughly to remove all soap residue, insert a towel into the device, and air dry it. Only wear the Underlay when it is completely dry.

Do not wring out the device, as this can damage it. Avoid harsh detergents, bleach, fabric softeners, ironing, and dry cleaning, as any of these can damage the coatings and void the warranty. Do not wear the Underlay while it is still damp, and do not use it over open wounds or injuries on the residual limb.

Choose the open version if maintaining suspension through skin contact at the distal end is important, or if you want to maximize airflow and evaporation. The open end lets the liner stay in direct contact with the limb while the Underlay extends beyond the liner to release heat and moisture. Choose the closed version if you have a more bulbous limb shape, or if you or your clinician prefer to avoid any impact from the open distal edge on fit or skin contact. Both versions deliver the same moisture-management and antimicrobial performance. When in doubt, your prosthetist can help you decide based on your limb shape and suspension system.

The Underlay carries a 45-day warranty covering manufacturing defects. Damage caused by improper care (such as washing above 40°C, using bleach or harsh detergents, wringing, ironing, or dry cleaning) is not covered.

The antimicrobial and cooling coatings are engineered to maintain performance through at least 20 wash cycles. After that, performance gradually declines with continued washing. Replacement timing depends on your wear and washing frequency.

No. The open version is designed to preserve suspension by keeping the distal end of the liner in direct contact with the skin. Traction-force testing confirms that this contact is sufficient to maintain suspension well beyond the demands of activities like running. By keeping the limb drier, the Underlay can actually improve liner grip and reduce moisture-driven slippage. A closed version is also available if added skin contact is preferred.

Yes. The Underlay is compatible with all major suspension systems, including pin lock, active and passive vacuum (closed version), lanyard, suspension sleeves, and seal-in or distal sealing ring systems. It works under all standard liner types, including TPE, TPU, and silicone. It must always be worn with a prosthetic liner.

The Underlay suits most transtibial prosthetic users across functional levels K1 to K4 who experience sweat, heat, humidity, odor, or moisture-related discomfort inside the socket. Three groups benefit most: patients with fragile or vulnerable skin (such as those with diabetes, vascular disease, or scar tissue), patients who generate high heat and sweat (such as active users, athletes, and people with hyperhidrosis), and patients with moisture-driven suspension issues whose limb becomes slippery inside the liner.

The Underlay helps with excessive sweating and hyperhidrosis, heat buildup that limits wear time, moisture-related skin irritation and maceration, odor, and moisture-driven slippage or instability inside the socket. Many users also find they no longer need to remove their prosthesis during the day to dry the limb.

Yes. In an Ethnocare case study of 15 lower-limb amputees tested during daily wear and high-exertion activities, users reported a 51% reduction in perceived humidity and a 38% reduction in perceived heat inside the liner, with an average comfort score of 8 out of 10. Controlled clinical testing using embedded humidity sensors also measured a 17% reduction in objective relative humidity inside the liner. These findings are consistent with established physiological research on how reducing skin moisture improves thermal comfort.

No. The Underlay sits under the liner inside your existing socket with no modification required. At 0.5 mm thick (adding about 1 mm overall), it does not meaningfully affect socket fit or alignment, so you can try it without altering your prosthesis.

The Underlay is built for everyday wear and high-exertion activity alike. In testing, users wore it during long-distance walking, cycling, hockey, treadmill workouts, wheelchair rugby, and physical labor, and reported that it stayed in place and continued managing sweat throughout. It is well suited to anyone whose daily life or activity level generates heat and moisture inside the socket.