1/4-19 thread size; 20.6 m o.D.; 13.7 mm i.D.; 2.0 mm width; used on k4 style straight fittings as a port seal
NSN 5925-00-612-7159
NSN 6620-00-411-4983
NSN 5990-00-288-1820
NSN 5960-00-275-7497
NSN 6150-00-550-7706
NSN 5915-01-424-6958
NSN 5915-01-341-2321
NSN 5999-01-468-0300
NSN 5960-01-056-4982
NSN 5960-01-502-3268
NSN 6320-01-106-4414
NSN 6150-01-424-0229