Item No.: SPHS5~SPHS30, SPHS5L~SPHS30LBall: 440C Stainless Steel, heat treated, HRC56 min Precision ground, polished Body: SUS304 Stainless steel Race: Brass Sliding contact surfaces: Steel/BrassPhone: +86-592-580 8851 / +86-592-580 7618Email: sales@ldk-bearing.com ; benjamin@ldk-bearings.com