For many people using a standard keypad is simply not possible because of vision and/or dexterity issues. The Chester Creek numeric keypad is the ONLY large-key numeric keypad that makes it a whole lot easier for anyone to crunch numbers like a pro-with big, 1" keys and bold, easy-to-read lettering for increased visibility and contrast. The Chester Keypad works well with all Chester Creek large-key keyboards as well as a stand alone or a supliment to your current keyboard, and has all the features of a typical keypad including the / key for division, and the * key for multiplication, 0 and 00 keys, and a subtle click to confirm each keystroke. With a USB connector there"s no need to worry about installing drivers, making it easy to use and very practical. Compatible with Windows Accessibility "Mouse Keys" to allow use of the keypad for mouse navigation, which is especially helpful for people who cannot, or prefer not to use a mouse. Mouse Keys is software that converts the numeric keypad into a directional mouse. When activated, each number on the numeric keypad controls a direction for the mouse or cursor. For example, pressing the 6- key on the numeric keypad directs the mouse to the "right". Pressing the 9 -key directs the mouse "up & to the right". Etc. Other keys on the numeric keypad have the functions found with the traditional mouse such as; single click, and drag-lock and settings allow for adjusting the acceleration and speed of onscreen mouse.