2.4GHz RF wireless technology & 6,500 IDs on 12 channels; Built-in optical trackball eliminates need for a mouse & saves valuable desk space; 11.75" wide & designed with a Windows(R) layout that includes an embedded numeric keypad; Membrane key switches offer a 5 million life cycle & are designed with a silicone rubber material to reduce noise when typing, offering a faster & quieter typing experience;