What Is a Canister Flush Valve?
Quick answer
A flapper alternative that lifts straight up like an elevator instead of tipping open. It takes a seal ring, not a flapper.
A flush valve design (common on Kohler toilets) where a tall plastic cylinder lifts straight up instead of a hinged flapper tipping open. Canister toilets take a replacement seal ring, not a flapper. No flapper will fit one.
Fixes that use this
Bathroom
Toilet Flapper Replacement: Get the Right Size the First Time
Most toilets take a 2-inch flapper; newer high-efficiency models need 3-inch. How to tell which yours needs, choose one, and install it in 10 minutes.
Time10 min Cost$5–$15 easy