... coefficient of friction3 Competitive price4 Variations of structure :A) Machined Type Needle roller bearing NA49, NA59, NA69,NKI, NKIS, BRI, TAFI,NAO ... , NA...2RS, etcB) Machined Type Needle roller bearing without inner ringRNA49, RNA59, RNA69,NK, NKS, TAF ... ,B,BH,M,MH,HK...OH,etcD) Drawn Cup Needle Roller ClutchesHF,HFL,RC,FC,FCB, etc5 Material: chrome steel1.Needle ...