This comes with a .4ohm coil. Adjustable wattage from 10 to 40 watts. If you are using 18mg juice, start at the lowest wattage setting. Anything much over 10 watts with 18mg juice will choke you up if you are new to vaping and trying to quit tobacco cigarettes. If your smoking habit was a pack and a half per day, 18mg is a good place to start, just dont hit that with wattage much higher than 10 watts until you get used to vaping. When I first started, I would cough a lot. Vapor is not smoke and it feels different in your lungs. It takes a bit of getting used to. Juices with higher PG percentages have a kinda harsh throat hit and this can cause coughing sometimes. Start with adjusting the wattage down and keep at it. You'll be vaping famously in no time at all.