The Kegco SF101-O2 O-ring is a replacement part for a Stout Faucet Spout. This O-ring is used at the threads to seal the spout to the faucet body and cannot be interchanged with other O-rings in the stout faucet. The O-ring will work with most popular brands such as Kegco, MicroMatic, Taprite, and UBC stout faucets. O-rings can deteriorate over time so it is always a good idea to have a few on hand.