I'm wanting to buy a kanger dripbox but I'm not sure which battery I should use. This would be my first device using an external battery and I want to make sure I'm getting the right one. I know the battery size would be 18650 but I would like suggestions on brand, mAh and amps. The drip box uses a constant 60w output, 3.7v output and uses a .2ohm coil. Any suggestions would be greatly appreciated. Thanks!