Once you have these concealed shelf hardware,no need to worry about ugly metal accessories ruining your home dcor.And it will create an illusion that the shelf is floating.Feel free to hang all kinds of shelves you want. Constructed from stainless steel,anti-rust and not bending,ensuring quality and longevity in wet weather.Impressive matte black color surface,comfortable touch feelings and heavy design style. A perfect space-saving storage that keep your home beautifully organized,enhance the flexibility of space.Widely used on backdrop wall in home,kitchen,garage,office,cafe,restaurant,store and more. The opening diameter is 10mm and the depth is 150mm.The error of 1mm exists,please drill the hole according to the actual condition.Note: Not applicable to the boards with a length less than 200mm (the width of the two brackets),a width less than160mm and a height less than 25mm. Product Dimension: 154mm x 100mm x 25mm(L x W x H),Hole Dia: 5mm,Thickness: 4mm.Package Content: 4x Brackets,16x anchors and 16x Screws.