Pob bearings muaj nuj nqi los ntawm kev siv cov khoom dov (steel balls) nruab nrab ntawm sab hauv thiab sab nrauv kom ua tiav kev sib hloov thiab kev txhawb nqa. Cov khoom dov zoo txo cov kev sib txhuam tsis zoo thiab txhim kho cov cuab yeej ua haujlwm ua haujlwm. Qhov sib sib zog nqus groove pob bearings muaj nyob rau hauv peb lub khw yog tsim nrog thawj Swedish SKF cov ntaub ntawv zoo, nrog ib txoj kab uas hla ntawm 10.5cm, ib txoj kab uas hla ntawm 16cm, thiab qhov hnyav ntawm 1.2kg. Lawv muaj ntau yam kev siv, tshwj xeeb tshaj yog tsim rau cov khoom siv xws li cov twj tso kua dej. Lawv cov qauv tsim thiab siab - cov ntaub ntawv zoo ua kom muaj kev ua haujlwm zoo thiab ua haujlwm ntev.
