The Kirby Morgan 530-099 Cover Retainer Screw, designed for the 455 Regulator Assembly, is compatible with the following:

Kirby Morgan 500-710 Diamond Helmet w/Posts P/N
Kirby Morgan 500-711 Diamond Helmet w/MWPC P/N
Kirby Morgan 500-700 97 Commercial Diving Helmet with Posts P/N
Kirby Morgan 500-701 97 Commercial Diving Helmet with Male Waterproof Connectors P/N
Kirby Morgan 505-086 455 Regulator Cover Retainer Assembly P/N: 505-086
Kirby Morgan 505-373 Regulator Cover Assembly P/N
Kirby Morgan 525-761 Water Shroud Kit for KM 97 P/N
Kirby Morgan 505-455 455 Balanced regulator P/N