- External numeric keypad for entering numerical data quickly and easily on a PC or notebook ,- X structure key design distributes the key press precisely and quietly ,- Practical roll-up organizer for avoiding cable clutter ,- Flat keys with a pleasant stroke ,- No software needed - just connect and you're done ,- USB connection , ,System Requirements: ,- Operation system: Windows 8.1/8/7/Vista/Mac OS as of 10.4 - Connection: USB ,- Width x Depth x Height: 8.6 x 0.9 x 13 cm ,- Colour: Black 2 years legal warranty only