Lot of 5, Vintage New Old Stock Amphenol USA Number 4 Wavy Retainer Rings for 78S and 86CP series female sockets and male plugs. Fits all except the 78S7L, 78S7C and 86CP7L 7 pin Large sockets and plug. These also work with the vintage Amphenol 110 VAC 60 and 61 series receptacles and plugs. Approximate ID is 1".