*4 x 4 Matrix Array 16 Keys 4*4 Switch Keypad Keyboard Module for Arduino Keypad
*4×4 matrix keyboard module, 16 button design
*Has 8 pins, 10 number 4 letters on the interface
*8-pins MR connect hole
*+3.0V~+5VDC voltage supply
*On board pulled-up resistors
*Lightweight and small size
*4 mounting holes on each corner for easy installation
*Dimension: approx. 6.8*6.6*1.0cm
 
Resources:
Interface 4×3 & 4×4 Membrane Keypad with Arduino
4x4 Keypad Interfacing With Arduino UNO