An auto-injector is a medical device designed to deliver a specific dose of medication quickly and easily. It is often used for emergency situations, such as administering epinephrine for severe allergic reactions or naloxone for opioid overdoses. The device typically features a spring-loaded mechanism that allows users to inject the medication into their thigh or upper arm without needing medical training. These devices are compact and portable, making them convenient for individuals who may need immediate access to life-saving medications. Many auto-injectors come with clear instructions and safety features to prevent accidental injections, ensuring that they can be used effectively in critical moments.