Pretty amazing shot illustrating German gasmask evolution during the war

On the left is an NCO wearing a "Selbstretter Draeger Tubben model 1914". Originally designed for attacking fortresses, and later used by pioneers involved in mine and chemical warfare. It weighed 5 kg and it provided oxygen for 20-45 minutes, depending on how hard the soldier was working. The compressed oxygen (bottle on the side) had to be transferred to a large bag (only partially visible) by opening the valve on the bottle, where it expanded. When the bag was nearly empty, a new burst of gas needed to be released into the bag. In the large cannister was a kalipatrone, to filter the air, and to condensate water and adsorbe the carbondioxide when the wearer exhaled. The wearer had to bite on a rubber mouthpiece, which also came with a clamp for the nose. No eye protection was provided, but often needed. An infantry company had 3 examples, as opposed to 25 for a pionier company. Pictures are always scarce and desireable. Of course, with the onset of gas warfare, it became clear that this was not enough and new ways to protect large numbers of soldiers needed to be put in place, bringing us to the NCO on the right. This gasmask tampon was one the first types to be issued. During 1915, the need for gasmasks became evident, but the protective measures were still in its infancy. The first types were gasmask tampons, of which at least 3 different models were issued in 1915, becomming better each time. This seems to be an improved mouth pad type, the 2nd or the 3rd of the first gasmasks. In all cases, chemicals had to be poured on it to provide protection, but it only provided limited protection. No eye protection was incorported in the design, but special goggles did exist. The second man from the left seems to be wearing some early type of gas mask tampon / mouth pad as well, but I could not find it in my books. It covers the entire face. Without any doubt, another scarce early 1915 model. Late 1915, the first proper gasmasks were issued, with complete facial protection and replaceable filters. These are typically referred to as Gummimaske (sometimes also called Gasschutzmaske M1915, Linienmaske, Bandmaske, Rahmenmaske). The device was constructed using rubberized fabric and the glasses were made of acetylcellulose. The filter stopped xylyl bromide (a benzene derivative) and chlorine gas, but the mask could not protect from the highly lethal phosgene gas (or dichlorocarbonyl). Later on, it also prooved to be inefficient when mustard gas was used (a chloro-sulfur compound), which went straight through the fabric. The mask on scene can either be one of the M15s (Type 1-4), as various changes were made during the course of the war and also better filter were made. Filter-life was 20-30 minutes. Note that the size "2" is marked on the front. It looks like this is either a type 1 or 2, as 3 had a smaler baseplate.

http://flic.kr/p/jZE3AT