From the website:
The vanguard of Dain's army, these Chariots run ahead of the Dwarves of the Iron Hills taking out any enemy scouts who dare to oppose them. Pulled by six goats at a time and with razor-sharp scythes attached to its wheels, anyone that is unfortunate enough to get in the way of a charging Chariot will end up considerably shorter!
Based upon the technology of the Coronus Grav-carrier, the smaller Caladius grav-tank is designed to utilise the firepower afforded by the heaviest elements of the Legio Custodes’ arsenal on a highly mobile, protected platform. Given the fusion of advanced systems and weapons, the Caladius is perhaps the most powerful battleline armoured unit of its size in the Imperium’s forces, utilising technologies and materials derived not only from the Dark Age of Technology, but from developments made as a result of the Great Crusade’s two centuries of warfare.