Welcome Adam. My advice would be to get a PV that is at least 3.7v and at least 650 mah. The ego or Riva would fit in that catagory as an example. Anything less than that you probably will be dissatisfied with and move up to something else. Also, after you decide what PV you want, but lots of extra everything, attys, cartos, batteries and lots and lots of juice. If you run out of something you may be tempted to run to the store for a pack of cigs until your supplies arrive.