This go kit is a generic replacement o ring kit for Hayward Star Clear 3000 4000 cartridge filters 75 and 100 sq ft Essential when replacing a part on your filter this kit includes the o rings needed for secure installation and leakage prevention Features . One Air Relief O Ring O 27 . Two Bulkhead O Rings O 43 . Two Bulkhead O Rings O 64 . One Tank O Ring O 429