Hayward 120 Sq. Ft. Star-Clear Plus Cartridge Filter | W3C1200 Style_Retro Pop Up Heads for the internal mechanism which

for the internal mechanism which is the operating system for the back-up valve

Filter Type - D

with all the parts you would need to be included

Engineered plastic body built in the USA by Waterway Plastics for corrosion and chemical resistance

Hayward 120 Sq. Ft. Star-Clear Plus Cartridge Filter | W3C1200 Style_Retro Pop Up Heads for the internal mechanism whichStarClear Plus single element cartridge filters offer excellent quality, value, and convenience. Features: No backwashing requirement saves hundreds of gallons of water and money per year. Constructed of the most durable materials for the toughest applications and environmental conditions Single locking knob securely fastens head to filter tank, eliminating bolts or clamps Long lasting, extra large cartridge element with precision engineered core