Fluidmaster 4-in Blue Flush Valve Seal for American Standard Champion 4, Eljer Titan 4 in the Residential Toilet Flush Valves & Repair Parts department at Lowes.com
Mansfield Flush Valve Seal Replacement 210 or 211. Fix Running Toilet & Stop Wasting Water. - YouTube
2" Universal Toilet Flush Valve Repair Kit with Adjustable Toilet Flapper | Flapper & Seal Replacements, Flush Valve Replacements | Korky Toilet Parts
How to Fix Your Toilet's Flush Valve Seal (With Photos) - Dengarden