Used on aircraft, hercules c-130. 1.710" overall length 1.000" overall width socket, relay, electrical - plug-in, 4 pole current rating: 15 amp for sz 16 contacts, 5 amp for sz 20 contacts, 0.112-40 unc-2b metallic threaded bushing (3 places) 2 on 1 end 1 on middle of other end