A plastic damper for attachment to a vibrating piano wire, the damper consisting of a single piece part having an end slot for turning by a screwdriver, and communicating peripheral slits for receiving the piano wire. One end of each peripheral slit has a slightly greater width than the rest of the slit, so that the piano wire can be inserted through this end of the slit, and locked against the damper by rotating it with a screwdriver, so that the relatively narrow major part of the slit "twist-locks" against the wire; the slight resiliency of the plastic facilitating the "twist-lock" action.