star washer,pushnut ,nut, washer 1.material: spring steel , 2.finish:black, Ni plating, zn plating 3.hardness: 42-50 star washer . pushnut ,nut ,lock washer, fasterner.material: spring steel ,stainless steelsize: OD17.4 ID9. 27 T 0.4 H2.1 I also follow custom requiryed sizeCertificate of Approval ISO9001:2000I can supply samples Stainless steel or Spring steel 8mm*15.15mm*0.3mm*1.6mm star washer