How a 3D printed breathable prosthetic liner scored a yearly average of 9.2 for comfort

7th December 2021

Many prosthetic limbs have a liner to make them comfortable to wear, and the Hero Arm is no exception. At Open Bionics, we took a unique approach to developing a breathable prosthetic liner with some amazing benefits that Hero Arm wearers love.

The liner in a prosthesis is the part which touches the skin. You might be wearing it all day in all different weather conditions, so it needs to be up to the job, and it needs to be comfortable. We manufacture the Hero Arm liner by 3D printing a medically certified elastomer, which is a flexible, rubber-like material.

Fluted design

The Hero Arm liner has a fluted design, with channels that run vertically down it. This creates a “concertina” effect which enables it to expand and contract to accommodate small changes in your arm size that may be caused by changes in temperature or growing muscles.

Here are some of the key features that makes the Hero Arm liner a firm and comfortable fit.

The Hero Arm features the lightest bionic hand on the market (12oz) for all day wear and comfort.

Ventilation holes

This fluted design is complemented by small holes throughout the liner which offer ventilation to make the Hero Arm more comfortable to wear in hot conditions. You can actually still feel a breeze on your arm when you’re wearing your Hero Arm because of the air coming in through the ventilation holes.


The liner can be removed for cleaning, and can even be swapped out for a larger one if your arm has grown (or shrunk). This means you can improve the fit of your prosthesis without having to replace the entire socket.

This year, the Hero Arm liner scored on average 9.2/10 for comfort from Hero Arm users.

3D printing

Each liner is made precisely to the 3D scanned model of every patient’s arm, following the evaluation from a prosthetist and we can design a perfectly fitting liner for a huge range of limb presentations. The entire design process is digital, which means we can precisely place the holes for the muscle sensors to perfectly line up and touch the skin giving you control over the Hand movements. The liner is included with every Hero Arm, and we hope you love these features when you wear yours.

This year, the Hero Arm liner scored on average 9.2/10 for comfort from Hero Arm users. If you would like to try the Hero Arm for yourself, register to find out more information here.