Alpha® DUO Fabricless Symmetrical Liner

The fabric-free outer Alpha Duo Liner combines the comfort of gel with the durability of silicone. Alpha Classic gel lines the interior, providing all-day comfort with skin-protecting mineral oils and vitamin E. Alpha Silicone covers the exterior, providing durability and protection with a satin finish for easy donning.

A One Gel Sock is included with each Alpha Duo Liner, which aids liner longevity and provides an air wick for optimal suction and vacuum suspension. This sock can be cut to match the trim line of the socket, improving knee flexion.

This liner can be combined with the movable One Seal to create a seal-in suction option for both AK and BK sockets – allowing the optimal seal location to be used.

Features and benefits

  • Thermoplastic elastomer (TPE) gel comfort on the interior
  • Silicone durability on the exterior
  • Easy glide finish for donning and doffing without lubricants
  • Ideal for suction suspension or elevated vacuum
  • Movable One Seal can be placed at the optimum point on the limb to obtain the largest possible area under vacuum
Product Part Number: D990 Category:


Symmetrical Profile

The symmetrical profile has increased thickness distally to provide increased comfort and protection. This tapers to 4.5mm proximally for easy donning, and a thinner edge when cutting. Being uniform circumferentially means that it can be rotated by the user to increase its lifespan.

  • 9mm distal end
  • Thins to 4.5mm proximally
  • Uniform circumferentially


Alpha fabric-less liners were developed for use with the One system. However, they can also be combined with the One seal and One sock for a seal-in solution.

Additional information

Interface Material


Amputation Level


Outer Fabric



Symmetrical 4.5


Pressure Relief


Extra Large, Large, Large Plus, Medium, Medium Plus, Small

One Gel Sock

Item NumberDescription
ONE-SOCK-SMOne Gel Sock Small
ONE-SOCK-MDOne Gel Sock Medium
ONE-SOCK-MPOne Gel Sock Medium Plus
ONE-SOCK-LGOne Gel Sock Large
ONE-SOCK-LPOne Gel Sock Large Plus
ONE-SOCK-XLOne Gel Sock Extra Large

One Seal

Item NumberDescription
ONE-SEAL-MPOne System - One Seal Medium Plus
ONE-SEAL-LGOne System - One Seal Large
ONE-SEAL-LPOne System - One Seal Large Plus
ONE-SEAL-XLOne System - One Seal Extra Large


Alpha Liner Manual
Alpha Liner Duo Size Guide

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