We present a novel low mass drift chamber concept, developed in order to fulfill the requirements imposed by the search for extremely rare processes, which require high resolutions (order of 50–200 keV/c) for particle momenta in a range (50–300 MeV/c) totally dominated by the multiple scattering contribution. The innovative concept in the chamber design is the separation of the gas containment and the mechanical support structure. We describe a geometry optimization procedure and a new semi-automatic wiring strategy with a feed-through-less wire anchoring system.