The device is called LectraJet M3 and has recently been approved by the Food and Drug Administration (or FDA), the government agency that oversees the approval of new medical devices. The approval is called a 510(k) and allows for the marketing and use of the device in the United States (US). Devices under a 510(k) do not need to have clinical trials performed. The researchers are performing this study in order to collect clinical data in a controlled environment. Non significant risk (NSR) devices such as the LectraJet may be studied in clinical trials with or without a 510(k). Currently there are several other disposable-syringe jet injectors that are also FDA approved for sale and use in the United States, including: 1) Biojector® 2000 , 2) Medi-Jector Vision, and 3) Injex™. These devices have been used to deliver millions of injections in a variety of healthcare settings. The LectraJet® is jet injector that is most suited for mass immunization campaigns due to the ability to power the device with a foot pedal as well as electricity and the speed with which immunizations can be delivered. It is designed so that vaccine delivery characteristics are the same as that of the licensed disposable-syringe jet injectors.