Some frequent piano tuning applications: From top to bottom: a tuning lever, a felt mute, a rubber mute, a felt temperament strip (still left), in addition to a Papps mute. Common equipment for tuning pianos consist of the tuning lever or "hammer", a range of mutes, plus a tuning fork https://hud-helmet74331.blogolize.com/the-ultimate-guide-to-piano-tuning-70147347