A coupling for connecting a compressed air source to an air motor, comprising a housing with a housing channel leading to a compressed air connection, a piston axially adjustable in the housing channel and force-loaded by a spring element, having an axially extending piston channel, wherein the coupling is designed to merge into a connecting channel when the coupling is connected to the air motor, wherein the piston is adjustable in the direction of the compressed air connection against the application of force by the spring element, wherein, in the absence of interaction between a pin element of the air motor and the piston, the piston is in a first position due to the application of force by the spring element in which the housing channel is shut off with respect to the piston channel by means of a first seal extending between the piston and the housing channel, and wherein the coupling is further designed such, that, when the coupling is connected to the air motor, in a second position of the piston there is a compressed air connection between the housing channel, the piston channel and the connecting channel, wherein the spring element runs between the compressed air connection and the compressed air connection side area of the piston, wherein radially extending openings (134, 136), through which the compressed air flows in the second position of the piston, extend from the compressed air connection side area of the piston channel, and wherein at least one exhaust air channel (160, 162) runs in the wall of the housing and passes through the wall in its compressed air connection side area, wherein the coupling is designed in such a way, that the exhaust air channel is connectable with the air motor, wherein the piston is adjustable by means of the pin element of the air motor having the connecting channel, in that the housing channel has on its inside a circumferential second seal which runs parallel to the first seal by means of which the pin element can be sealed with respect to the housing channel, characterized in that a distance between the contact region of the first seal on the contact surface and the second seal being defined such that, when the first seal bears against the contact surface, an impact surface between the piston and the pin element runs between the contact surface and the second seal. wherein radially extending openings (134, 136), through which the compressed air flows in the second position of the piston, extend from the compressed air connection side area of the piston channel, and wherein at least one exhaust air channel (160, 162) runs in the wall of the housing and passes through the wall in its compressed air connection side area, wherein the coupling is designed in such a way, that the exhaust air channel is connectable with the air motor, wherein the piston is adjustable by means of the pin element of the air motor having the connecting channel, in that the housing channel has on its inside a circumferential second seal which runs parallel to the first seal by means of which the pin element can be sealed with respect to the housing channel, characterized in that a distance between the contact region of the first seal on the contact surface and the second seal being defined such that, when the first seal bears against the contact surface, an impact surface between the piston and the pin element runs between the contact surface and the second seal.