Every Monday The Director of the Mütter Museum takes a minute to showcase an item from our collection. This week Robert showcases a vaccine gun, also known as a Jet injector. A jet injector is a type of medical injecting syringe that uses a high-pressure narrow jet of the injection liquid instead of a hypodermic needle to penetrate the epidermis. They are powered by compressed air or gas, either by a pressure hose from a large cylinder, or from a built-in gas cartridge or small cylinder. They are used for mass vaccination, or as an alternative to needle syringes for diabetics to inject insulin. As well as health uses, similar devices are used in other industries to inject grease or other fluid.