Magic Arm size: 7&11inch. Material: High Quality stainless steel & aluminum alloy. Max load: 10kg/22lb. Articulating design, with one knob(one tightening screw) locks all 3 joints (two ball and one friction). Loosen the screw, move all three joints into whatever position you want. Makes you a comfortable use when you need any angle of the device. with two 360° Ball Heads with 1/4" screw threads for versatility connect options