The boxmod is a very simple design that works great. You not only get better battery life, but the battery stays at 3.7 volts longer than a standard e-cig battery, giving you that new battery vapor longer. This is a battery box with a switch and an atomizer connector that is assembled with lead free solder and epoxy There is also a master on/off switch that shuts everything off so it can't turn on in your pocket or purse. It runs on one 14500 lithium ion battery, that will last the average vapor up to eight hours. The box can be made as either a 901 or a 510. I have adapters available to make the 901 box able to use a 510 atomizer or a KR808D or Vapor King cartomizer and an adapter to let the 510 box use a 901 atomizer or KR808D or Vapor King cartomizer.The mod does not come with an atomizer, batteries, or charger. For all the mods you need LI 3.7 volt batteries. Alkaline or regular rechargeables will not work.