This was one of various revolver designs produced by the Liege firm of Henrion, Dassy & Heuschen. It was produced in small numbers in the 1910s and distributed under a variety of trade names.
The HDH double-barreled revolver used a large-capacity cylinder with a series of staggered chambers, made up of an inner ring of chambers and a wider outer ring. To fire off from both rings, twin firing pins were mounted on the hammer. The chambers were arranged in such a way that the gun would alternate barrels between each shot, rather than firing off both barrels at the same time.
The assembly of the frame was based on the standard Spirlet tip-up frame, using a break-action hinge located over the cylinder rather than under it. These revolvers were built with both 20-round cylinders, chambered in 6.35mm, and 16-round cylinders, chambered in 7.65mm.