A system for attaching a prosthetic limb to a residual limb. In embodiments, the system includes a liner having an elastic sleeve adapted to accommodate a residual limb and a socket adapted to surround the elastic sleeve, the socket having a vacuum port, an inner surface, and a vacuum channel extending radially outward from the inner surface and longitudinally within the socket, the vacuum channel being configured so as to be in fluid communication with the vacuum port when the residual limb and liner are disposed in the socket. In some embodiments the sleeve has an annular groove disposed on an inner surface of the sleeve and a flexible annular seal extending radially inward from an inner surface of the sleeve below the groove, the annular groove being adapted receive at least part of the annular seal when the annular seal is moved toward the interior surface of the sleeve.
