The Core 2.1 is the updated version of the Core 2.0 now features a non-rebuildable 3D atomizer as opposed to the rebuildable Atomizer on the Core 2.0. The difference in atomizers makes Core 2.1 a better quality option since the non-rebuildable atomizer negates the need to purchase tools to dismantle the atomizer itself. The Core 2.1 features one-button functionality and a fully heated ceramic vaping surface, not to mention the carefully tuned heat settings and aluminum/glass vapor pathway. Apart from those amazing features, the Core 2.1 comes with a 3150 mAh Li-Ion battery pack that takes about 1 hour and 45 minutes to fully charge.