Device for fastening two adjacent containers

The system for attaching auxiliary fuel tanks (2) or natural gas cylinders (4) side-by-side to the underside of a car chassis comprises stirrups (6) which fit around them and whose ends (14) emerge between them The outer ends (8) of the stirrups are bolted to the chassis while the ends which emerge in the center fit into an adapter bar (10) bolted to the chassis.