I use the prepacked oil with the battery, it's clean and easy to use and dispossable. (you can return used oil things in the envelope they provide). It's easy to take out with you including a spare because it's so small to carry. This is my second attempt to stop smoking and these vapes are enough for me. they are also reasonably priced although for me the main aim is to stop smoking. there are different flavours but for me, I prefer the original tobacco flavour, the others are ok but a bit sickly for me. Delivery is fast and there are offers for multiple packs and you earn points that you can spend on your next lot. I'm really happy with them.