Interpuls’ Long Life Pulsators are designed for heavy-duty working conditions. Building on the strengths of its simple, reliable, variable-speed alternating vacuum pulsator, Interpuls has redesigned and used new materials for even better performance in any milking system–parlor, bucket or pipeline. “Dustop” felt air filter has large surface area for excellent filtration of even microscopic particles. Cover design gives perfect seal for best protection in dusty conditions. “Surematch” slide and valve system features new improved synthetic valve plate material for friction reduction and smooth interaction. Diaphragm material has been selected for its fatigue resistance qualities. LL90 Style has stainless steel cover. 60:40 Ratio.