Bayonet Double Contact Base Socket. Specifications include: 1-1/4" overal length, 1/8 IPS male threading (3/8" diameter), 9" black and white leads, rated 105º 600 Volt, 2-1/2" Long Mounting Nut, Nut has 1-5/8" Spaced Holes Center to Center, 7/32" holes.