This is the Traxxas X-Maxx 8S Complete Differential. This comes pre-assembled and includes both the ring and pinion gear, as well as bearings.
These are an excellent option for quick replacement of a damaged diff. It's also great to keep as a spare in the toolbox in case of a break-down while out bashing if you don't want to spend time re-building smaller components while out running for the day.
