Adafruit Industries Adafruit Industries Membrane 1x4 Keypad + Extras
Punch in your secret key into this numeric membrane keypad. This keypad has 4 buttons, and since every key has its own wire line, no matrix code is required - just treat these like every day switches. The membrane is soft and has a removable paper backing to expose a strong adhesive so you can stick this on an enclosure and feed the cable through a slot. Its a simple keypad but that's why we like it. We include a 5-pin extra-long header strip so you can plug this into a breadboard with ease.
Adafruit Industries Membrane 1x4 Keypad + Extras