The Tough-Claw Clamp with Diamond Plate & Short Arm by RAM MOUNTS fastens to rails or bars 0.62 to 1.14". Rubber pads on the clamp provide additional stability. Mount any compatible surface to the 2-hole AMPS diamond plate. Find the perfect angle with a 1" short arm with two b-sized ball sockets. The clamp has a 2 lb weight capacity, 1 lb under heavy-duty use.