What does this artifact tell us about the First World War?

What this photo tells us about WW1 is that chemical weapons were being used in the war. The Germans were the first to attack using chemical weapons, stunning their enemy with chlorine gas and killing many. After this attack their enemy was quick to react by creating the gas mask in order to provide protection against the Germans chemical attacks. After the first gas mask was made using cotton pads and cloth, they kept improving on the design and preventing damage to the eyes, and neck. Though the gas masks protected soldiers against the chlorine gas they weren’t able to protect against the gas which was used later on in the war. The gas mask marked a milestone as it was a symbol of the use of chemical weapons.