The T258 is a high-quality vacuum valve. After the valve is laminated in the prosthesis socket, and the stump is placed in it along with a silicone or gel liner, the valve releases air from the socket as the limb pushes it out and does not allow it to return, thereby creating a vacuum and holding the prosthesis on the stump. It provides  negative pressure in the socket, discharging the air to the outside through the valve. It can be used with a vacuum socket system as an alternative to the classic pin-lock technique. These components are not load-bearing. Wide valve. Used in double lamination and temporary leg prostheses.