https://www.homedepot.com/p/KOHLER-Seal-for-All-Single-Flush-Class-5-and-Class-6-Canister-Toilets-K-GP1059291/202524230 https://www.lowes.com/pd/KOHLER-1-in-Flush-Valve-Seal-for-Kohler/3508524 Looks like this is available at the Capitol Expressway Home Depot and the Sunnyvale Lowes.