It is a device used when pressing the spring of the injector body.
Compared with pressure lever, it is easy to use, so it is preferable in hospitals and places where the frequency of use is high. 
[How to use]
Set 'Lock' to 'Locked' on 'Injector Body' to prevent false fire.
Put the 'injector body' inside the 'pressurized box', then close the lid of the pressure box completely and open the injector body! "Prepare the injector body to fire in 1 ~ 2 seconds!"
(* However, do not open the lid of the pressure box by excessive force more than 80 degrees.