This size 55 liner M40 helmet is rare. A helmet with a size 55 liner would fit into a very small helmet shell, such as a size 60. Since helmets in this size were produced in much smaller quantities, a size 55 liner inside a corresponding small shell size, such as a 60, is quite rare and sought after by collectors. Perhaps, the rarest size of the M40 helmet produced is size 60. The M40 Stahlhelm, used by the German military during World War II, was typically made in shell sizes 62, 64, 66, and 68. Size 60 is considered rare because relatively few were produced compared to the larger sizes. Collectors highly prize this size for its scarcity. It is not in perfect condition. There is weathering of the paint as you may see. There is also a (possible combat) dent and a degraded leather strap and buckle.