6Pcs Hidden Floating Shelf Brackets Concealed Invisible Heavy Duty Shelf Support Bracket for Wall Shelf 10mm x 100mm Features: These floating shelf brackets are made from cold-rolled steel and plastic, high hardness and durability. It is easy to install them, firm and stable. The concealed design is more beautiful and save space. The product is widely used in the decoration industry. How to use it: 1. Punch holes on the wall. Hole diameter: 12mm; Hole depth: 73mm-75mm; Hole pitch depends on the length of the board. 2. Insert the expansion tube end into the wall and rotate tightly the hexagonal handle to open up the expansion to hold tight the wall. 3. According to the hole pitch on the wall, punch holes on the board( thickness15mm). Hole diameter: 10mm; Hole depth: 100mm. 4. Fix the board to the wall. ( If the expansion doesn't open up, hold the expansion and rotate the handle, the expansion will be concave, make it convex with fingers, rotate tightly the handle, the expansion will open up, keep up the situation 20 seconds, loosen the expansion up and go to the second step.) Specification: Material: Iron + Plastic Color: Brown Size: 10mm x 145mm / 0.39" x 5.71" Quantity:6Pcs. Note: Size for manual measurement, there may be a 0 to 1mm error, belongs to the normal phenomenon. And due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Package Included: 6Pcs x Shelf Brackets