The keyboard is 60.0mm x 76.5mm, the flat cable is 90.0mm long, with 15mm 7pin connector. The 7 pin keyboard is super slim and ready to go. Use this numeric matrix keypad to punch in your secret key. The keypad has 12 buttons, arranged in a 3x4 grid like on a telephone. It's made of a thin, flexible membrane material with an adhesive backing (just remove the paper) so you can attach it to nearly anything.
The keys are connected into a matrix, so you only need 7 microcontroller pins (3-columns and 4-rows) to scan through the pad.