3x4 Phone-style Matrix Keypad

This keypad has 12 buttons, arranged in a telephone-line 3x4 grid. It's made of plastic with sturdy plastic buttons. The keys are connected to a matrix so you only need 7 microcontroller pins (3-columns and 4-rows) to scan through the pad. 

There's a great Matrix Keypad Arduino library that will work great with this item with minor adjustments. It comes with 7 header pins pre-soldered on for easy plugging. Starting from the left there are three column pins, and then to the right are the four row pins.

Check out Adafruit's detailed guide with wiring diagrams, libraries and example sketches for all sorts of matrix keypads.