1. Premium Quality: Our tap cartridge is made of high-quality stainless steel and ceramic, which is sturdy and durable, serving you for a long period. 2. Valve Insert: the outside diameter is 7.5mm, the inside diameter is 4mm, the total length is 73.8mm. It is the most commonly used size of the tap cartridges valve. 4. Easy to Install:This kit contains two ceramic faucet valves (1 x blue and 1 x red). The red and blue O-rings on the bottom of the spool make it easier to distinguish and install, cold water with blue bottom, hot water with red bottom. 3. Good Sealing:Faucet valve replacement has a black rubber lock washer that is easy to use, seals the tap well, and save the trouble of replacing the faucet again, making your life easier. Thank you for coming to our store. If you have any questions, please send me an email and I will reply to you immediately.