This magic arm UURIG R002 is made of metal and it's very sturdy. Used with my field monitor 5.7" with a battery, and the monitor didn't move a inch. My friend have a Atomos Shogun Inferno 7' and the arm held it with no problem too
The magic arm is wonderful, all metal and it has some weight. I've liked it. But I'm sorry that I didn't see the L- driver for uninstalling it as it was described in the product photo.