● Koob cov kabmob muaj peev xwm loj
● Tsis tshua muaj kev sib txhuam coefficient, kev sib kis tau zoo
● Muaj peev xwm thauj khoom siab
● Cov ntu me me
● Lub puab txoj kab uas hla qhov loj thiab lub peev xwm thauj khoom yog tib yam li lwm hom bearings, thiab sab nraud yog qhov tsawg tshaj plaws.