This is a 4x4 matrix of tactile buttons solidly mounted on to a PCB with an 8-pin single-row 0.1" pitch header. The switches are clearly numbered with white silkscreen printing. Each switch gives satisfying tactile feedback when pressed.
The 0.1" single row male header is breadboard friendly. The overall dimensions of the PCB are 39mm x 43mm.
This is a great way to experiment with matrix decoding on the Arduino!