... roller bearing:KR,KRV,KRE,STO,RSTO,NATR,NATV,NUTR CRY,RNA22..2RS,NA22..2RS Material:20GrMo ,GCr15 Metric and inch ... :Rolling body guiding,yoke type track rollers,full roller type CRY :Inch system,plain retaining ring,axial guiding, yoke type track ...