The Rallongé, or lengthened Verascope differs little from the standard focusing models of the time. It's distinguishing characteristic being the lengthened film back mounting flange. This allowed use of a special quick-loading back. By installing a block at the end of the film back guide, standard plate and roll film backs could be used. In spite of being able to use a standard roll film back, Richard made lengthened roll film backs pacifically for the Rallongé. In this camera set, the two magazine backs are numbered one and two. Back number one shares the same serial number with the camera body (as per usual, hand etched on the camera body to match the magazine). Back number two is serialed within several hundred of back number one. This suggests the numbering of backs may have been done as an independent operation. When someone ordered a camera with two backs, the camera was serialed to match back number one, and then a number two back was "grabbed off the pile" and included in the kit. Lens matched, of course, was more critical. Most stereo cameras will have either consecutive numbered lenses, or at least numbers very close together, probably from the same production batch.