Oring ( 10381 ) use on Base Bottom of Fleck 2500/2750/3600 ( and Hydro Quad 5600 ).
O-ring = 2 7/8" O.D. x 2 5/8" I.D. x 1/8" Thickness
Also, used on manual filter caps ( 2 1/2 inch versions, PN MC7004 ) and 3/4" In & Out Head ( MD717105 ).Also used on MacClean / CUNO models MCA1001, MCA1001M, MCA1501, MCA1501M, MCA2001, and MCA2001M
