PSS Shaft Seal, Marine Shaft Seal, Gland Seal, is the most popular marine mechanical seal worldwide. It is installed as standard equipment by most boat builders, and ship yards. The PSS Shaft Seal is also recognized as the premiere retrofit (aftermarket) seal on the world market. Certified by Bureau Veritas, ABS & Rina: Boat builders / yards recognize the advantages and value of installing the PSS as it eliminates the maintenance, constant adjustment & cost associated with traditional packing type glands. Aside from these benefits, the PSS Shaft Seal helps to eliminate water in the bilge (100% water tight) & wear to the propeller shaft. The PSS Shaft Seal can be easily retrofitted and is available for shafts ranging from 3/4" (20mm) to 6" (150mm).