... chioce. 3)Many hardness 4)Long serivce time Blue Pu Spring 1)Made of CPU, can be machined by CNC lathe ... oils, silicone oils, biodegradable oils, ozone, cold oxygenMain applicationStatic and dynamic seals (standard and special), wipers, O-rings, back-up rings, flange seals ... tests are made under laboratory conditions.Remarks: Custom any size and any color accroding your request Blue PU Spring