[90°] I have several of these and I'm not afraid to put digital recorders, monitors with batteries, etc. on them.
They really hold a lot of weight right where you put it.
The 1/4 screw design on both ends is MUCH better than just the stud with a plastic 'locking' collar.

[Ball Head] I use them to clip my Quantum battery packs to various light stands. They've got the place for clip mounted items, but about a million threaded mounts for everything else.

[90°] Not much to say besides it's adjustable and works as you'd expect. I expect many years of use based on the material its made of.

[Ball Head] Purchase this over the summer, to help a teacher use her iPhone during live and pre-recorded instruction. It works great! Fantastic design with numerous mounting options for whatever accessory you might have.
Very comfortable to hold with the side grips, or you can mount to a tripod or clamp with 1/4”-20 screw.
Zero complaints!

[90°] This was for a vintage tripod I had to repair. (Machined a new bolt and everything....) Works just fine and looks good, too.
This is a surprisingly nice little ball head. It feels well made, and the screw knobs are comfortable to grip. It pans nicely, and the ball locks down firmly. The plate also allows a few cm of slide forward and back. The level on the plate knob is a good idea, going to have to test that on uneven setups eventually.
My ONLY complaint is that the mark for rotation angle is on the back side, for me, if the knobs are on my side of the head. Not worth making a fuss, but it would be better placed on the other side.
Overall, I recommend it.

[1x 1/4"-20 Male] I used it to clamp to a speaker support to get some GoPro footage, ample locations to attach the cheese plate to for a level shot.

[1x 1/4"-20 Male] I use this mount on a Z6 with the Ninja V, mounted on the side with the SmallRig L bracket that slides out some. It gives room for an on-camera mic.

Back to this mount though ... its small/low, sturdy, easy to adjust, rotates ... just works. Definitely recommend.

[1x 1/4"-20 Male] I use this mount on a Z6 with the Ninja V, mounted on the side with the SmallRig L bracket that slides out some. It gives room for an on-camera mic.

Back to this mount though ... its small/low, sturdy, easy to adjust, rotates ... just works. Definitely recommend.

[1x 1/4"-20 Male] Needed sturdy mount to attach to tripod and allow for additional accessories to attach to for live-streaming church. This was the perfect mount.

[Yes] Exactly what I needed for the top of my light stands so that I can change the angle of the lights. These seem to be well made and durable.