This simple platform was designed to mount a 3.25"x2.125" breadboard on top of a RPi. This was intended to mount on top of my Raspberry Pi Stand and Raspberry Pi Fan Platform. It also allows plenty of clearance for airflow to the fan.

Since the board outline and hole pattern has not changed on the RPi, this is compatible with RPi versions 1/3/4/5 B/B+ boards.