Hayward EC50AC Perflex D.E. Pool Filter, EC50AC filter with clamp; recommended for round pools 28 to 33 feet and oval pools 18 by 39 feet also for in ground pools with different pump only the pump is recommended for above ground pools Bump handle causes the flex-tubes to clean themselves of dirt and filter powder; integral check valve prevents system backflow whenever pump is off Heavy-duty filter tank injection-molded of high-strength for dependable, corrosion-free performance 1-year limited warranty