Item No.: SPHSB3EC~SPHSB12ECBall: 440C Stainless Steel, heat treated, HRC56 min Precision ground, polished Body: 304 Stainless steel Race: PTFE composite Sliding contact surfaces: Steel/PTFE compositePhone: +86-592-580 8851 / +86-592-580 7618Email: sales@ldk-bearing.com ; benjamin@ldk-bearings.com