Floating wall-mount AV shelves are 5mm thick black tempered glass with an unobstructed surface - Shelves are height adjustable along the 13.6in wall bracket - Steel brackets support 15.4lbs per shelf; Aluminum wall bracket is sturdy and lightweight; Tempered glass is more resisitant to scratches/shattering - Mounts to a single wall stud/concrete wall (wood screws/concrete anchors are included) - Cable management cutouts along the wall mount bracket; Pre-scored knockouts on the top/bottom caps.