指尖棘轮

指尖棘轮，单向转动，可发出嗒嗒声。安装方向如图。否则可能没有声音或者声音不清脆。 "Fingertip ratchet, one-way rotation, can make a clicking sound. Installation direction is as shown in the figure. Otherwise, there may be no sound or the sound may not be crisp."