SmallRig Adjustable Magic Arm with Dual Ball Heads 1/4” Screw Mount Clamp - 3873
20mm ball heads, each with one1/4 "-20 screw and stretchable pins that prevent twisting. Key Features - Material(s): Aluminium Alloy, Stainless Steel. - Magnetic wrench at the bottom of the thumb lever for tightening thumbwheels.