... PP, NATV, NATV PP, NUTR and NUTR XRNA22, 2RS roller-type bearing:Diameter of this wheel size same as STO seriesOnly slightly ... ; COuter ring of need end-to guideNATR, NATR-PP type roller bearing:NATR series supports rollers, including outer ring, inner ring, needle ... speed, can also absorb shocks of axial load Cam follower/Roller bearing/RNA22..2RS,NA22..2RS/NATR/NATV/NUTR....