Cov khoom siv grooved reducers yog siv rau kev sib txuas yeeb nkab grooved, feem ntau yog nyob rau hauv cov yeeb nkab reducers, qhov twg qhov chaw nruab nrab ntawm ob lub yeeb nkab kawg txuas nrog tib txoj kab ncaj, uas tso cai rau qhov loj me ntawm cov dej ntws hloov pauv.













