See: https://www.raspberrypi.org/products/model-b-plus/ The Model B+ is the final revision of the original Raspberry Pi. It replaced the Model B in July 2014 and was superseded by the Raspberry Pi 2 Model B in February 2015. Compared to the Model B it has: More GPIO. The GPIO header has grown to 40 pins, while retaining the same pinout for the first 26 pins as the Model A and B. More USB. We now have 4 USB 2.0 ports, compared to 2 on the Model B, and better hotplug and overcurrent behaviour. Micro SD. The old friction-fit SD card socket has been replaced with a much nicer push-push micro SD version. Lower power consumption. By replacing linear regulators with switching ones we’ve reduced power consumption by between 0.5W and 1W. Better audio. The audio circuit incorporates a dedicated low-noise power supply. Neater form factor. We’ve aligned the USB connectors with the board edge, moved composite video onto the 3.5mm jack, and added four squarely-placed mounting holes. The Model B+ is perfectly suitable for use in schools: it offers more flexibility for learners than the leaner Model A or A+, which are more useful for embedded projects and projects which require very low power, and has more USB ports than the Model B.