Dual Ball Heads with 1/4"-20 Screws - Magic Arm 3873 features 1/4"-20 screw on each end for attachment of DSLR camera, action camera, LED light, Flash, etc. Max. load capacity is 6kg/13.2lbs Anti-twist Design - The ballhead magic arm 3873 features one 1/4 "-20 screw and stretchable pins that prevent twisting when using Adjustable and Stable - The adjustable thumb lever helps secure ballhead at an appropriate angle and comes with a small magnetic wrench at the bottom to tighten the thumbwheels 360° Rotatable Flexible Adjustment - At both ends of the ball head clamp there are notches which leave more space for flexible adjustment of ball heads as well as accessories mounted thereon Lightweight, Durable - This item weighs only 88/3.1oz, making it easy to carry around and store. Aluminum alloy and stainless steel materials makes it durable and stable to use