Mounts to Studio Clamp to hold lightweight fixtures or props. It is easily adjustable and holds its position without locking. Measures 21.5" (55cm) long, 0.5" (1.2cm) diameter, with a 5/8" hexagonal stud with a 3/8" female thread at one end and a 5/8" stud with a 1/4-20 male thread at the other end.