Abstract: A device for detachable fastening of an assembly part on a receptacle, the device including a base having a contact flange, at least one clamping arm formed on the contact flange, which snaps resiliently into a clamping position in a radial latching direction. An axial insertion opening is formed in the contact flange. A mandrel is removably inserted into the insertion opening. The mandrel extends as far as a blocking actuation section in a blocking position accommodated in the insertion opening to limit a displacement of the clamping arm from the clamping position or widen the clamping arm in the latching direction into the clamping position. The clamping arm includes an actuation release section which can be actuated by an actuating pin inserted via the insertion opening to urge the clamping arm resiliently from the clamping position opposite to the latching direction.