Review on Water-Saving Toilet Flapper Compatible with TOTO Flapper Model THU140S - Long Lasting Rubber Seal, 3-Inch Replacement - Includes Stainless Steel Chain and Hook - Easy Installation (Pack of 1, Blue) by Justin Verslues

This damper didn't work with Toto's toilet. I ordered based on the information listed under the cover. It says return is ok as long as it hasn't been used. To know if it's leaking or not, you need to install it. It's a period leak! For me this experience was frustrating so I searched and found a generic valve from Toto and not a third party valve, it costs more but you get what you pay for. The damper from Toto worked great. It doesn't work for me and I can't return it, hence the one star rating. You can check my order history to see if I actually bought both.