https://www.bestplumbing.ca/Catalog/toilets-urinalsAndparts/toiletAndurinalparts/toiletgaskets-sealsAndwaxrings/toto-thu475-seal-gasket-for-nh-drain-valve-pk10-1236214
TOTO THU475 SEAL GASKET FOR NH DRAIN VALVE (PK10) | Best Plumbing - Showroom
seal gasket