Repair kit for Centek 5 in. exhaust thru hulls with externally mounted rubber flapper. Thru Hull Flapper Repair Kit 5 in. | Centek 1200345 Replacement exhaust thru hull flapper Inlcudes rubber flapper and 2 mounting screws Exclusively for Centek 5 in. exhaust thru hulls with flappers - not for other makes