1.high performance product 2.different surface finish is available 3. professional manufacturer Retaining RingMaterial by steel or stainless steel.SW, SP, WR, M2400 RW, RB SeriesDimension according to standard or customs designMetric and SAE size is availableStandard: DIN471, DIN472, DIN6799, DIN5417, DIN7973...Different surface finish is availableSize from 30mm-400mmCustoms design welcome!