Product Name:filter cartridges spa pool;Function:Capture Small Organisms,rust,gravels,algae;Certificate:WQA,IAMPO;Compatible With:C900 CX900RE PA90 C-8409 FC-1292 PXC95;Replacement Period:4-5 Days;Outer Diameter:8.9375 ;Inner Diameter:4 ;Length:17.375 ;