1.90 degree angle bracket is widely used in shop or store as a support bracket. 2.White baked enamel finish iron folding shelf bracket. 3.People can set a board on the bracket, and then put things on the board. No. There are three stop positions on this bracket for 3 different sets of degree openings. It will easily open to the 90 degree angle because sprint loaded latch allows it to slide past the two sets of notches for the smaller degree openings, but closing takes a bit more effort because you must press and hold the bracket release lever tight enough to get past all 3 sets of degree stop positions. .