Kohler Part GP1059291 Toilet Tank Canister Valve Seal, 6-pk. Genuine Kohler part. Compatible with Kohler Class 5 and Class 6 canister toilets. Kohler's proprietary formulated yellow seal fights conditions that cause leaks. Formulated to withstand wear from chemicals and general use. This seal has a 2-1/2 " inner diameter and a 3-1/2 " outer diameter. Certified to ASME standard. This KOHLER Canister Toilet Seal is chemical-resistant to help provide durable use in class 5 and class 6 compatible canister toilets. This seal has a 2-1/2 in. I.D. and 3-1/2 in. O.D.