With 13 settings, these supports lock in place when lifted. Lift again, and they release to fold down.
The range of motion depends on how close they are to the pivot point, but the maximum operating arc is 112° from horizontal. Commonly used for drafting tables and reclining chairs, they are 9" long overall, with an 8 1/2" pivot arm.
Sold in pairs; requires #8 screws (not included).