This O-ring has a 3 1/8" ID and a 1/8" cross-section to fit the O-Ring Cap for 15-Gallon Utility Jugs (Part No. 2577-041) as well as the O-ring cap for our Dual-Handled 5-Gallon Utility Jugs (Part No. 2560).
This O-ring does not fit our original Scribner Utility Jug Cap (Part No. 2561), which uses a flat gasket.