Duttek Numeric Keypad Retractable USB Cord Financial Accounting with 18 Keys for Mac Windows XP Laptop Desktop PC (Black) Digital keyboard with 18 keys, Ideal for notebooks without a number pad Keys operate smoothly and quietly. USB Keypad comes with 18 keys of 0-9 number keys, Del, Enter, Back Space, Num Lock, + - * /. USB wired connection with storable USB connector hides cable to safely transport and reduce cable clutter, Simple plug and play installation. Space saving ergonomic spill resistant 18 key USB numeric keypad with back space for improved productivity. If you use MAC, you can't use the Num Lock keypad, If you use the Windows series system, Num Lock keypad in normal work, Windows 32/95/NT not support USB device.