The 40" Grip Arm with Hex Stud is a 2 1/2" grip head mounted on the end of a 40" piece of steel tubing 5/8" (16mm) in diameter and finished with a faceted hex stud to keep lighting fixtures in position when they are placed on the end of the arm. The surface of the tubing is painstakingly machined to create a rough texture to ensure a non-slip surface. The 2-1/2" grip head consists of a pair of rotating aluminum discs attached to a 5/8" (16 mm) receiver. The discs have four different sized "V" shaped jaws to accept any accessory with a 5/8", 1/2", 3/8" or 1/4" mounting stud or tubing. The "V" shaped jaws have "teeth" that grab whatever is mounted between the plates securely. The 2-1/2" grip head features an oversized ergonomic "T" handle and dedicated roller bearings designed for maximum torque.