Several manufacturers are often involved in the construction of a motorhome. The vehicles are then homologated (approved) in stages. For example, the powerhead from FIAT with a COC (level 1) can be assembled with a frame rear axle attachment from e.g. Al-Ko (COC level 2) to form a chassis. Dethleffs, the on-board equipment manufacturer, then builds a motorhome on this and issues a Dethleffs COC (level 3) accordingly. Often there is only level 1 (e.g. Fiat) and level 2 (Dethleffs) as the chassis manufacturer builds directly on the ladder frame. When it comes to issues such as the permissible tyres or the reduction of load capacity, the COC of the last stage is always decisive.