The Ethnocare Underlay TT Open is a thin textile sleeve worn directly against the residual limb underneath a transtibial prosthetic liner. Its moisture-wicking knit uses capillary action to move perspiration upward toward a breathable evaporation section that extends above the liner trim line. The distal end remains intentionally open so the distal portion of the liner can maintain direct contact with the skin, making the design particularly relevant for suspension systems where distal liner-to-skin contact is important. The textile also incorporates StayFresh odor-control technology and StayCool technology.