This o-ring is designed to use with Hayward Pro-Grid, Micro-Clear Vertical Grid D.E. filter and Pro Plus series models S311SX, S311SXV, S360SX and also use with sand filter pro series S210S, S244S, S310S, sand filter series S240, S200. Compatible with Hayward Super Star-Clear Cartridge filter series C2000, C3000, C4000, C5000 and Multiport valve SP0410X, SP0740DE, SP1078. Weighs 3.6-pound.