This 18-Key Numeric Keypad only weighs a quarter of a pound and is less than three-and-a-half inches wide which makes it extremely portable and space-saving. The keyboard's spill-resistant design helps to prevent fluids from staying inside, which would otherwise cause damage to the keyboard. Membrane key switches provide a quieter typing experience with lifecycle lasting up to five million keystrokes. Wired/Wireless: Wired; Connector/Port/Interface: USB; For Device Type: Windows™ Computer; Keyboard Design: Numeric.