... time 2,popular on us market 3,strong manufacturing capability inch ball bearing 1633Features:1),Shield / closure: Open,Teflon Sealed,Rubber ... , Ceramic6),Retainer: PTFE, Nylon, PEEK Or Stainless Steel7),Bore Size:from 1mm to 10mm8),Outside Diameter:from 3mm to 30mm inch ball bearing 1633