4 x 4 Matrix Keyboard

A 4X4 Matrix 16 Key Membrane Switch Keypad for Arduino is the most commonly used input device in many of the application areas like Arduino project, digital circuits, telephone communications etc. A matrix keypad consists of a set of push button or switches which are arranged in a matrix format of rows and columns.
8-PIN MRconnect hole
+3.0V to +5VDC supply voltage
On-board pulled-up resistors