Material: Galvanized solid steel. Will not rust or bend. This floating bracket set includes 6 pieces. Dimension: 70mm(L) x 75mm(W) x 14mm(H); Mount hole distance: 42mm. Advantage: Strong enough to hold your shelf steadily. Can be used in areas with limited space or to hang an invisible shelf on the wall. With a premium finish and durable construction, these shelf brackets offer reliable performance and are ideal for supporting floating shelves. Kindly Note: We recommend mounting into a wall stud for maximum support. Each bracket holds up to 15 lbs. For heavier shelves, add extra brackets to distribute the weight. Scope of use: Use a router to remove 42mm from the wood. Designed to be fully hidden behind your shelving, with a small profile for easy concealment.