Solid Brass Brushed Nickel Rounded Interior Shelf Clamp. Designed to be used to secure a shelf for lightweight articles. Clamps should be secured to wall with screws (included) in studs, or with Molly-type anchors. A Nylon tip brass set screw secure the glass. Maximum 5" (127 mm) glass protrusion from wall is recommended. Recommended use tempered glass for shelve. 1-15/16"(49mm)Wide X 1"(25mm)Deep.