900 Standard Keyboard Platform made of phenolic, an ultra-strong, remarkably thin (1/4?) composite that?s non-toxic, durable and easy to clean. Standard 900 platform designed to support nearly all standard keyboards and to fit most desks. Available with any of our mouse options. Dimensions: 19" w x 10 5/8" d. Humanscale 5G adjustable arm mechanism offers all the advantages of the keyboard arm 4G, including simple dial-a-tilt keyboard angle adjustability but it has wider track for more stability. The new state-of-the art in keyboard technology, the 5G combines easy dial-a-tilt and height adjustability with the strongest arm on the market. The Humanscale 5G is the premier keyboard mechanism from the worldwide leader of articulating keyboard systems. Humanscale 5G Mechanism Features (Adjustable Keyboard Arm): -Intuitive, knob-free height adjustment (6 1/4? range from 5? below the mount to 1 1/4? above the mount) -Easy, dial-a-tilt platform tilt adjustment from 0° to -15° for safe keying -22? track allows the unit to slide fully under the desk for storage, or all the way out for complete access -Base 360° swivel -Standard Track Length 21 3/4" -Track width 5 3/8" -Alternate Track Lengths 16? and 18" -End of Track to Beginning of Platform 6" -Max Depth Below Bottom of Keyboard 1/2" -Unmatched stability for sure keying and mousing -Made of steel for strength and durability -Lifetime Warranty