A prosthetic sleeve and socket system, the sleeve including dual flaps or skirts concentrically arranged about the sleeve and configured to form a sealed chamber between the sleeve and socket when the sleeve is inserted into the socket. An air permeable material is interposed between one of the skirts and the sleeve to maintain a continuous interconnected air layer therebetween. An expulsion valve is provided to allow air contained within the sealed chamber to be forced out of the chamber ahead of the sleeve when it is inserted into the socket, and a powered vacuum pump maintains the vacuum thereafter, if needed. The system allows for a substantial reduction in size of known sockets and permits, in some instances, the disposal of bulky suspension straps currently in use to force the socket against a residual limb.