Mount Hole Size: 12 x 5mm/0.47" x 0.2"(L*W); Mount Hole Distance: 42mm/1.65" Shaft Size: 10 x 70mm/0.4" x 3"(D*L); Rectangle Base Size: 70 x 14 x 4mm/2.75" x 0.55" x 0.16"(L*W*T) Main Color: Silver Tone; Material: Metal;Weight: 280g; Dimension: 70 x 75 x 14mm/2.8" x 3" x 0.55"(L*W*T) Product Name: Hidden Bracket; Package Content: 4pcs x Hidden Bracket Easy To Install: Drill a 7/16'' diameter, 3'' depth hole in the your shelf, and then mount the brackets on the wall with bolts, slide the shelf onto brackets. (Mounting Bolts are not included) Wide Application: Ideal floating shelves brackets for furniture bookshelves of 20mm-30mm thickness, partition care, used for background walls of homes, kitchens, garages, offices, cafes, restaurants, shops, etc.