Feature: It is a great replacement for a broken keyboard tray Solid structure: Made of sturdy heavy duty cold rolled steel construction with powder coat finish, more powerful than ordinary slides Adjustable Height: Adjustable holes heights to meet different person's height requirements. Under Desk Keyboard Rails: The stand desk keyboard tray slide are used to add keyboard trays or drawers underneath desks, allows you to open or close the keyboard tray, makes better use of the space under the desk. Height-Adjustable Tray Track: The under deck pull out lift with L-shaped corner brackets with 5 adjustable holes for vertical adjustment, offering approximately 9mm increments. This provides 6.1 to 10.7 cm (2.4 to 4.2 inches) of space beneath your desk. Solid Construction: The hidden under desk lifting bracket made from heavy-duty 1.4 mm steel plate with a galvanized finish for rust resistance, load: 22-25kg (48-55lbs), please check the level and alignment and parallel with the inside of the tray. Smooth and Silent Slide: The under table extension roller track features high-quality bearings for ultra-smooth and quiet operation, easy to use with no sticking or noise. The end of the rail is fitted with a spacer to avoid impact. Widely Use: The keyboard tray under desk slide can be used for DIY work desk keyboard support sliding rail, music piano holder, under-desk sliding shelf and table extension slides, etc. It is easy to install and can be tightened well, please keep the left and right slides at the same height.