Shelf brackets are designed for strength and are used to mount shelves to walls. Brackets are sized at slightly over 90 degrees to provide a surface to keep items stationary. Use #7 pan head screws to mount brackets, 1/2 in length screws to fasten shelf and 1-1/4 in screws to fasten to stud (sold separately). Shelf brackets must be fastened to a wood stud for proper installation. Safe working load of 100 lbs. when brackets are spaced 32 in apart. Shelf brackets are compatible with wood, plastic or metal shelving.