The hypospray is operated by holding the nozzle firmly against the patient's arm or neck, and pressing a trigger on the head of the device. This converts the medication into a high-pressure, microscopic, aero suspension stream that can penetrate both clothing and the epidermis, before passing into the patient.
The hypospray can be adjusted for a wider distribution patter that yields a high absorption rate. However, in this configuration the medicine cannot be injected into areas of the body deep beneath the skin.
The hypospray delivers small amounts of medication from a vial, which contains a reservoir of the appropriate medicine. These small vials plug into the base of the hypospray (see above). The preferred point of injection is usually the large carotid artery on each side of the neck, though many inoculates are administered to the upper arm.
A second model of hypospray, the field hypospray, is standard issue with every Starfleet med kit. These hyposprays are intended for medical emergencies outside sickbay, or when basic resources are not accessible.
The field hyposprays hold five different medication ampoules at one time. These concentrated emergency medicines are already loaded into the hypospray as standard, and are automatically diluted with a saline solution when the device is activated.