Original late war experimental M31 Zeltbahn with a faint R.B.Nr. stamp. This variation was only produced between May and July 1944 by, I believe, only one maker as part of an experiment to improve the design. The button holes reverse direction every other hole, presumably in an attempt to make them button together better. Apparently, the experiment was not considered a success as this rotating button hole pattern ceased production fairly quickly. There are only a few types of zeltbahns that are considered rare and this is one of them.
Unfortunately, there are a few holes, most are rather small but there is a roughly 2in. square hole. Other than that, the material is actually quite nice looking with good color. It has the lower quality print often found in these later zelts. All steel buttons. I believe a few buttons are missing but not many. The "lighter" side of this also has a slightly greenish color overall and the "darker" side is slightly more of a brownish color overall, although the sides are extremely close to one another. In short, the holes do suck, but this is still a beautiful zeltbahn.