Review on 🔧 MOSHUSO 7-inch Magic Arm Friction Articulating Arm with 1/4" Screw for Field Monitor, LED Light, Flash | Max Payload 3 kg/6.6 lbs by Jamie Prezant

Thoughtful design - can be adjusted with one hand. Attach one end to a clamp, etc. and the other end to an accessory. Take the accessory, loosen the handle, install the accessory, tighten the handle. Will it hold four pounds? Possibly, but when you fully extend your arm, that's a BIG torque. I would attach this arm to a clamp or cage to be on the safe side. The arm itself weighs 8.5 ounces, so it's not light. Internal parts steel, external aluminum. Balls and threads are made of steel. Great design, super easy to use and you can position your accessories in literally any position and angle. A single center knob locks the position of the arm and ball heads, while serrations lock the center pivot in place.