im wondering if anyone knows why? I bought the toptank for my wife and it works fine on a subvod kanger battery or my cuboid or koopor but wont read (shows 9.99) on the kbox mini. why? thread length is the same as my subtank mini and subtank plus. wont work on the kbox. which is a bummer as she wants simplistic top fill and variable wattage. I dont want to give the cuboid or koopr because mainly she thinks they are to big and bulky. she likes small. one would think it would work on the kbox mini as it is kanger but it doesnt. and help or info is greatly appreciated.