A sanitary insertion unit (1), including an insertion housing (6), in which insertion housing a valve having a valve piston (10) is provided, which valve piston is slidably guided in the insertion housing and can be moved from a resting position under the pressure of the inflowing water against the restoring force of at least one restoring element (11). The restoring unit has at least one movement damper (12, 13), which damps or brakes the movement of the valve piston from the resting position to the open position.