Shelving Brackets.
Miss Pitt got it pretty much.
You can just measure how long the legs are, or take the broken one it. I tend to do that myself. Then you can match it up, also I tend to get one of the guys that work there to go looking for it. I walk in and stop the first one i see, 'hey this is broken i need a new one' and look at him with a dumb expression till they go find it for me. Unless I already know where that section is.