Wing-Nut® wire connector is specially designed contoured wings provide a secure grip for extra leverage on maximum wire combinations. Live-action spring expands to accept wire shape and size with no pre-twisting required. Square-wire spring threads directly onto conductors for fast, secure connections. Deep skirt helps protect against flash-over and turned-back strands for maximum dielectric protection. Accepts 2 #18 to 3 #12 AWG wire combinations. Rated for 600 Volt maximum.