This thing is absolutely awesome. The key concept to understand is that tightening the one thumbscrew at the center tightens the center joint and both ball joints at the ends simultaneously. Even better, the center joint has teeth which make it hold its position (albeit with a little play) while the ball head joints are still moveable. It truly is kind of magical how you can adjust three separate rotating joints with one set screw. Once tightened, the hold is very secure. For a phone, it’s almost overkill. For a mirrorless camera, I would be cautious, especially with a long, heavy lens attached. The arm clamp works well for thin tabletop edges and tripod legs, but it falls short of being “magic”. The phone holder is fine, but nothing out of the ordinary. It should hold most phones securely.

I’ll point out that both ends are 1/4” male. I will likely invest in a couple of adapters to give me more flexibility. For example, I can’t attach this to a tripod head as-is. There are other versions which might have been more suitable for me, but this one was available for me to evaluate through the Amazon Vine program, so this is the one I landed on.