The 6.5 gallon carboy is shorter and fatter than the 6 gallon carboy. It is approximately the same height as a 5 gallon carboy with a wider footprint. A #6.5 or #7 rubber stopper will fit in the neck of this carboy, with the #7 being preferred.
We highly recommend using a Brew Hauler to carry glass carboys – it makes carrying full carboys easier and safer!