Pneumatic injectors (aka jet injectors, injection guns) were a common tool for large scale vaccination programs (smallpox, polio, etc). It turns out they can cause a horrific amount amount of cross-contamination, so thankfully they aren't used anymore. These days, the only place you'll see on is in a movie, where they're still a great way to dramatically administer a medication (or more often for a villain to administer an implausible truth serum or knock-out drug).

Along those same lines, this project is for a prop (i.e. fake) pneumatic injector. The aesthetics don't fully match the original device, partially due to a desire for something that looks a bit more sci-fi, but mainly so all the moving parts could be fit inside. The main design requirement is for the injector to give a convincing puff of air, and ideally a nice "pssshht" sound, and also to look like a medical device. The obvious requirement is that it be safe, and not be capable of piercing