Description: STURDY MATERIALKeyboard tray clamp and rails accessories are made of sturdy and durable steel, wear resistant, thickened material, strong bearing capacity and more stable. ROTATABLEThe C clamp can be rotated 45, for irregular desktop thickness within 4cm for a variety of L shaped corner tables. WRIST PROTECTIONClamp and rails Set for DIY Keyboard Tray, and your wrist is naturally relaxed, avoiding bending, effectively avoiding wrist soreness, and more comfortable to operate. EASY TO INSTALLEasy to assemble the clamp and rails, and then clamp it on the desktop, no need to punch, no damage to the desktop, easy installation. DESIGN The elongated guide can be elongated 20cm length, smooth solid steel balls make the guide more silent, the guide can be removed and separated, easy to clean, simple and convenient. Specification: Material: Metal Size Chart: 20cm-40cm/7.87inch-15.75inch Package Includes: 1 Clamp Rail Set For Keyboard Tray(Does not include wooden board) Note: Please allow slightly errors due to manual measurement and different monitors.