Black Friday: lifetime access is on a special offer in the app, until November 30. Black Friday: special offer on lifetime access, until November 30. Download
미늘톱니바퀴는 기계에서 회전을 제어하는 데 사용됩니다.mineultopnibakwineun gigeeseo hoejeon-eul jeohaneun de sayongdoemnida.The ratchet is used to control rotation in machines.