SEALS are used to create a barrier between a rotating and a stationary surface. They function to retain or separate lubricants or fluids, keep out contamination, and contain pressure. V-Ring seals are all rubber seals used primarily to exclude dirt and other contaminants. Wipers are flexible lip exclusion seals. They are used to wipe contaminants from a shaft. Scraper exclusion seals have a scraping edge that maintains contact with the rod regardless of any rod deflection or motion. Hydraulic seals and pneumatic seals are designed for the reciprocating motion that is common in hydraulic and pneumatic applications, such as cylinders. Rod seals   Piston seals are radial seals. The seal is fit onto a shaft with the sealing lip contacting the housing bore. Double acting or bi-directional seals are effective when sealing in both directions.