Abstract: An air system prosthesis for amputees includes a hollow body with stiff peripheral walls and an open end and a cup shaped partition defining with the walls a first socket. A hollow stump support second socket with stiff peripheral walls is snugly nested within the first socket upon the partition. The second socket includes spaced apart inner and outer walls with cup shaped closed ends interconnected and hermetically sealed at their other ends defining a continuous air chamber between the inner and outer walls adapted to snugly and frictionally receive a human stump. A manually operated air pump and pressure relief valve is mounted upon the outer wall having a normally closed air passage adapted for applying pressurized air to the chamber and for selectively exhausting air therefrom.