best 21700 box mods of 2018

Best 21700 box mods of 2018 | will it replace 18650's? Recently we noticed that more and more manufactures released 21700 box mods and battery cells, such as Eleaf iStick Pico 21700 kit, Wismec Reuleaux RX2 21700 kit, IJOY CAPO 100 kit and IJOY ELITE PS2170. Usually a 18650 battery is around...