Basic Keyboard Arm and Tray - Black, 28 KEYBOARD TRAY: An ergonomic adjustable keyboard tray built with high quality materials ADJUSTABLE COMPONENTS: The tray adjusts with the use of a knob in the back that when loosened allows for 6 of vertical adjustment and 15 of tilt to help reduce stress and fatigue SPACE SAVING BENEFITS: Eliminate the keyboard from your desk and store it 100% beneath the surface for maximum workspace VARIETY: 28 tray holds an extended keyboard and mouse, the 24 tray holds a standard keyboard and mouse, and the 20 tray holds a standard keyboard DESIGN QUALITY: Made in America with premium commercial grade materials and backed with a Lifetime Warranty