This is a replica of the jet packs used in the Great War who where crucial to win the war. This type of Special Operations squad had great mortality as the task of this squad was to penetrate enemy lines, cut supply lines and attack from behind. Due the extreme mortality, of the dangerous "leaps" and the close quarts combat, survivors of these type of squad where considered heroes for their own countries. Examples are: Henry Johnson, Charles Whittlesey and the Red Baron.
This early machines were created during the war and without much testing they were introduced in the battleground as they showed to be highly effective in the trench war. This exact jet pack was the version of the allies and consisted of twin rocket engines, with four individual injectors. Two for the fuel and two for the oxidizer, as well as a manual air pump to initiate the system. It also had a safe for close combat so it won't fire by an accident.