This is the Microsoft Sculpt Comfort Keyboard model V4S-00001. The Sculpt Comfort Keyboard is packed with ergonomic features including a contoured keyset, removable padded palm rest, and palm lift. These features are designed to encourage a more natural, relaxed positioning of the arms, hands and wrist, providing greater comfort and helping to avoid injury during extended use. Microsoft believes in the constant pursuit of excellence, and is always looking for ways to improve the comfort and productivity of our hardware. The new split spacebar with backspace functionality on the Sculpt Comfort Keyboard is the perfect example. Research shows that 90 percent of people use only their right thumb to hit the space bar, and that the backspace key is one of the most frequently used keys on a keyboard.