The unique design of the Heifetz mute allows the player to adjust the muting effect by sliding the metal tension clip down or up, muting more or less in consequence. The metal tension clip is the part that is stamped “HEIFETZ”. Made of the highest quality materials, many professionals swear by this unique mute. The original Heifetz mute used to be very similar, but with a somewhat different design.All string players must have at least one mute, and there are three important factors to believe. First and foremost, ease of use. How quickly can the mute be put in place or removed? How important is this to you? Orchestral players every so often only have one measure to install or remove a mute. Secondly, sound quality. The goal of the mute is to lower the volume only, not dampen the good quality of your instrument. Regarding overall sound quality, the degree to which a mute “rattles” when not in use but still on the strings between the bridge and tailpiece is important as well. Third is aesthetics. Truth be told, many players believe the importance of overall look and feel, trying various mutes to find out what works and looks best on their instrument. Fortunately, mutes don’t seem to be too expensive, so this can be a somewhat low cost endeavor.