The PSS Shaft Seal is the #1 selling marine mechanical seal worldwide and is installed as standard equipment by many of the worlds most reputable boat builders and boat yards. The PSS Shaft Seal is also recognized as the premiere retrofit (aftermarket) seal on the world market. The PSS Shaft Seal can be easily retrofitted and is available for shafts ranging from 3/4” to 6” (20mm to 150mm).