for 213 & 313 & 413 Armstrong IB Steam Traps and 3-LD/33-LD Armstrong Liquid Drainer & 3-AV/33-AV Armstrong Air Vents and 2313HLS/2413HLS High Leverage Drainers Gasket Dimension: ID: 4.38-in & OD: 5.13-in Armstrong part no A22284-1