The Extreme Duty Seal on the Allied Winch is specifically designed for winch applications in the most adverse conditions such as sand and mud or submerged in water as found in oil sands tailing ponds, hydro-mining, dredging or equipment rescue in muddy conditions where the water or slurry level could rise above the top of the winch.... Allied's Extreme Duty Seal features a pair of precision machined mechanical face seals, backed by heavy duty seal rings to withstand severe wear and to keep out water and harsh, abrasive material. It solves the problem experienced by other winches where the gear train has to be overhauled frequently when the regular lip seals fail to prevent the ingress of water and sand. The extreme duty seal option is available on Allied winch models H8L, W8L, H12E and W12E. This option comes with an extension hose to relocate the winch case breather above the water level on the tractor.