This SBIR Phase II award is for further research on a variable- geometry socket for above-knee and below-knee amputee prostheses. This socket will provide for easy and precise adjustment of the fit of the socket and therefore should greatly increase comfort. Large volume changes from muscular atrophy of the new amputee will be easily accommodated. The system is comprised of a generic polymer-socket shell, five standard liquid-filled positioning bladder-pump units that align the stump in and vary the volume of the socket, and a generic elastomer-foam liner. Full suction-socket capability is retained with this design. The variable geometry socket system has an estimated market in the USA of $40 M/year with a prosthetics cost saving potential of over $100 M/year.