General Information: The Dutch Model 1934 addressed problems of its predecessor, the Model 1927. Artillerists complained that the earlier helmet produced irritating sounds in windy conditions. This made it difficult for soldiers to hear orders. In addition, the helmet had to be removed when using a telephone because the brim was in the way. The solution to these two problems was to create a version of the helmet with the cutouts on the sides. This solution was similar in concept to the German Model 1918 ear cutout helmet. In other aspects, including the liner, chinstrap and frontal badge, the M34 was identical to the M27. Both helmets had an opening in the back. This allowed the helmets to be attached via a leather strap to a backpack. All the M34 helmets were manufactured by the Verblifa company in The Netherlands.
The M34s used by the Dutch Royal Navy and Marines had an anchor emblem with a crown. The Royal Dutch Military Police procured M34s which were spray painted black in the factory. 
Displayed Example: I purchased this helmet in 2012 from German Helmets Inc. The helmet is complete and unaltered from its circa 1940 state. The original owner wrote his name in red ink in the back. I cannot quite make it out, but it is something like “Hemmil.”
Collector Notes: The badges on these helmets were made of copper and many early collectors could not resist removing the black paint and polishing these to make them pretty. Of course, nowadays that kind of thing is frowned upon. Do not buy one with a nice shiny badge. Hold off for a better example.
Another thing to look out for are the versions of the M34 that were issued to Civil Defense Forces in the mid-1950s. These are readily identified by their reddish leather liners and distinct grey-green color that is different from the darker green color of the wartime versions. In addition, there were many M34 that were repainted black for use by police, fire brigades, air raid defense, civil defense and the like.
A Dutch Model 1934 in its original wartime state can be a challenging thing to find. When they hit the collector market, however, they tend to be only moderately expensive.
* Pfitzer, S. Originally published in Die Woche 1940. This copy from: World War II in Details. http://ww2images.blogspot.com/2019/02/dutch-soldiers-surrender-at.html Posted February 4, 2019. Accessed May 22. 2022
 De Joode. 2007. pp58-59
 De Joode. 2007. pp76