... 4140, S50C4. We have 15years experience in making rubber moulds, especially for rubber molds of electronic rubber parts, automotive rubber parts, ... . WSR's rubber workshop Description: Description: Material: comply to RoHS, silicone or rubber (NR, SBR, NBR, EPDM, CSM, CR, HNBR, ... we can reach ±3 shore A tolerance Color: for rubber, usually black, for silicone, can be in any color as you want Machine ...