This is a real nice find and a great example of the transitional year of early 1940 when the Quist factory seemed to have some supply issues with their mid war Big Foot decal and so were using ET eagles to fill the gap. Here we have a classic M40 Quist helmet with a low rear lot number of 478 putting the production date to early 1940. This lot number is very interesting because all other known examples are the holy grail M40 DD Waffen-SS configuration. But not this one. The inside paint is dark pea green the same paint you would expect to find on a smooth M35 factory issued helmet so this one might have been completely covered in smooth pea green and then changed last minute to 1940 specs of dark textured feld grau. The decal is your classic textbook ET Heer and not your usual Bigfoot Quist which can be seen on other early M40 Quists helmets I’ve seen on other dealer’s websites in the past. The chinstrap is faintly marked but is marked Rahm & Kampmann Wuppertal 1940. I believe this helmet might reflect the transitional year in between M35 specs and M40 specs when they were just phasing out the pea green smooth paint for feld grau paint and having a unique Quist bigfoot eagle decal produced and applied. If you have a keen eye you will notice subtle differences between Quist bigfoot decals applied on M35 helmets verses the ones later applied to M40 helmets. I believe there was a small gap of maybe a few months between these two bigfoot Quist decals in which ET decals may have been used to fill in the gap. Just my best guess as a passionate lover of this fascinating hobby.