At the end of the 40" grip arm you will find a baby hex pin with six milled flat surfaces. Allows mounting the light fixtures or accessories on the end of the grip arm like a mini boom. They won't rotate due to the set-screw of that fixture or accessory locking onto one of the sides of the hex pin. 40" Hex Grip Arm with Big Handle has a 2 1/2" grip head mounted on the end of a 40" piece of steel tubing 5/8" (16mm) in diameter. 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. The grip head uses a non-slip aluminum friction disc that will maintain its durability over time that offers the user positive locking strength and precise control and is constructed around a solid steel central bolt with a fixed solid pin to secure it to the aluminum casting for increased strength and durability.