Keypad: 2.7 x 3.0 in (6.9 x 7.6 cm)
Cable: 0.78 x 3.5 in (2.0 x 8.8 cm)
Maximum Rating: 24 VDC, 30 mA
Interface: 8-pin access to 4x4 matrix
This keypad has 16 buttons, arranged in a 4x4 grid. It's made of a thin, flexible membrane material The keys are connected into a matrix, so you only need 8 micro-controller pins (4-columns and 4-rows) to connect the key pad.