Our cartridge pumps incorporate some of the most advanced Features in the industry, Features developed from service in a wide variety of uses including racing, cruising, sport fishing and demanding commercial duties. For L450, L550, and L650, the design has been improved with easy-to-install Dura-Port discharge ports to eliminate stress cracking caused by over-tightened hose clamps. Where applicable the pumps are delivered including both a straight and a 90° smooth elbow Dura-Port as well as a removable check valve.