N4w Oil Seal, or Wr Wear, or Ring Back Up are used in hydraulic cylinder, prevent the ... resistant and airtight are the good features.N4w Oil Seal, or Wr Wear, or Ring Back Up. They are used in hydraulic cylinder ... .1. Products Name: N4w Oil Seal, or Wr Wear, or Ring Back Up2. Applications: hydraulic cylinder or cylinder3. Place of Origin: Hebei Province, China4 ...