This device allows you to check the resistance of any 510 or eGo-threaded atomizer. It also allows you to check the output voltage of your 510 device, including Pulse-Width Modulated devices.. You can also attach an atomizer and a device at the same time to test its voltage under load! The Omnitester has an internal rechargable battery, and comes with a USB to Micro-USB cable for charging. There are a wide range of uses for a device like this. You can simply test your resistance and use it as an ohm-meter. You can also test the voltage drop of your mechanical mod by attaching a mod and an atomizer at the same time. You can even check the output voltage of a mod that's set to wattage mode and get results in real-time, instead of using an Ohm's Law calculator. If you're feeling really crafty, you can even attach a gooseneck extension or two, and use the mod while it sits on your desk, without even having to pick it up! Whether you're a veteran or a beginner, this is a handy tool that shouldn't be passed up!