Federal Specification a-a-50552, Nema/ansi Fb-1, Military Specification Number W-F-406d, W-F-406e, W-F-408d, W-S-610d | Culus Federal Spec. W-F-408e, Nema Fb-1 | Ul Listed | 5.2500 in X 5.2500 in X 1.5000 InSouthern Tier Electric Supply