Adapter and prosthesis system

The invention relates to a device for connecting a pump with a in a prosthesis stem (36) existing through-hole (42), wherein the device at least one channel (6) a first output (4) for connecting to the existing in the prosthesis shaft (36) through bore (42) and a second output (14) which is connectable with the pump, and comprises at least one valve (24), said valve (24) can be brought into a first mode and a second mode wherein the valve (24) in the first mode, a one-way valve and in the second mode is a two-way valve, wherein the at least has a channel (6) a third output (56) existing for connecting to the in the prosthesis shaft (36) through bore (42) and a termination element (58) connected to the third output (56) is connectable and in a connected state flowing through the third output (56) in the at least one channel (6) is prevented.