These Pico Dolly 7" Articulating Arm has two nicely machined metal sections. The one section has a locking accessory shoe mountthat can be removed and used with either a 1/4"- 20 female or male thread, so it fits any need. There is a ball joint on the base allowing it to swivel in most any direction. The other section also has a ball joint and a threaded 1/4" - 20 post. The large knorled knob allows you to loosen both ball joints, top and bottom, move the arm into whater position you desire, and lock everything up with the twist of one knurled knob. Simple to use, yet extremely versatile design. Available in two lengths: 7" and 11" heights.