The standard Black Mega-Coupler # MLB. Has a 1/2? × 1 1/4" Hex Head Bolt with the Light Source Wing Nut. Our Mega-Coupler has solid nut tabs that won’t break off. Mega-Coupler uses standard half inch by 1-1/4 inch long hex head grade 8 bolts to secure your load. Bolt head locks into hex milled pocket so that you can tighten the nyloc nut while the clamp is installed. Has industry compatible 14 mm thick base. The Mega-Coupler fastens from (1-1/4" Pipe) 1.66" OD to 2 " OD truss tube.