Features: Ergonomic Design: Relieve elbow pain extend desktop space clean desktop correct bad sitting posture. Easily stow away at the bottom of the desk to make more room for the desk. Foldable Bracket: Thickened steel baking paint bracket stable and not shaking strong bearing weight bearing 25kg. Practical and professional suitable for home or office use. Easy To Install: No need to punch no damage to the desktop just clamp it on the edge of the table and tighten it. The C-clamps hold everything tightly in place and adjust with simple hand tightening. Size Details: we have two types for you to choose full size(l*w): 20x4.5cm/7.87x1.77inch a: clamp width: 6.5cm/2.56inch applicable desk thickness: 1-5cm/0.39-1.97inch b: clamp width: 9cm/3.54inch applicable desk thickness: 1-8cm/0.39-3.15inch. Package Included: You will get 2pcs x keyboard tray clamp 8pcs x flat head screw 2pcs x gasket in one package.(Note: Without tray without slide rail) Specifications: Type: A B Material: Cold Rolled Steel MDF Color: Black Size:About Full Size(L*W): 20x4.5cm/7.87x1.77inch A: Clamp Width: 6.5cm/2.56inch Applicable Desk Thickness: 1-5cm/0.39-1.97inch B: Clamp Width: 9cm/3.54inch Applicable Desk Thickness: 1-8cm/0.39-3.15inch Gasket(D*T): 35x2mm/1.38x0.08inch Package Included: 2pcs x Keyboard Tray Clamp 8pcs x Flat Head Screw 2pcs x Gasket Note: 1. Due to the light and screen difference the item's color may be slightly different from the pictures. 2. Please allow 0.5-2 cm differences due to manual measurement.