The Raspberry Pi 3 is the latest addition to the Raspberry Pi family. It is a third-generation Raspberry Pi. It replaced the Raspberry Pi 2 Model B in February 2016. Compared to the Pi 2, it has the following features:
A 1.2-GHz 64-bit quad-core ARMv8 CPU
802.11n onboard wireless LAN
Bluetooth 4.1
Bluetooth Low Energy (BLE)
Also, like the Raspberry Pi 2, also has the following features:
The form factor of the Pi 3 is identical to that of the Pi 2 and Pi 1 Model B+. The Pi 3 has complete backward compatibility with the Pi 1 and 2.
Note
The product description for the Pi Zero and Pi 3 can be found on Raspberry Pi's official product pages:
https://www.raspberrypi.org/products/pi-zero/
https://www.raspberrypi.org/products/raspberry-pi-3-model-b/