Available for 37$ the USB Keypad, is a 19 key + 13 hotkeys layout with 2.4 GHz. RF technology. It built-in high precision 1000DPI trackball. Its Portable and tiny design can be used for travel, school, or any other working environment.Measuring 114 x 134 x 25mm and weighing 143grams, the Brando’s Wireless USB Keypad with Trackball also sports Microsoft Windows 2000/XP/Vista OS