I had a SVD which I used in 18350 for out and about(carrying spare batteries for long times out) It died pretty fast. The micro switch in it is broke and it ain't easy to get apart to fix it. I started playing with mechs because I'd kill a VW mod about once a year. I now know the SVD often has this problem so wouldn't buy another. Shame because it is really nicely built otherwise and their other products all get great reviews. They might have fixed it in later versions but it is hard to know which one you are buying.