Maximize Desk Space With This Steel Corner Sleeve For 90 L-Shaped/Corner Desks - Increase Workspace For A Keyboard And Mouse While Resting The Arms On The Desk Extender; Usable Surface Is 25X13.1In - Supported Desk Thickness 0.5-1.5 In - The Knob-Less Clamp Allows For Enough Clearance Of Knees/Chair Armrests; For Wood Or Metal Desks; Permanent Or No-Drill Installation - The Sturdy Desk Shelf Ships Fully Assembled; Foam Pads Protect The Surface - The Desk Tray Is Backed For 5-Years