When it came time to pick a winner for this category, the choice was clear — Vapen Clear, in fact. Other cartridges sold by competitors sometimes contain such nonessential ingredients as propylene glycol, vegetable glycerin, polyethylene glycol, or coconut oil. But Vapen doesn't resort to using any unnecessary filler material. The absence of additives and the presence of thick terpene taste make for a full high with a full flavor that's glaringly apparent from the very first drag. Lab tests show that these crystal clear cartridges contain up to 99.52 percent total active cannabinoids. For those of you keeping score at home, that's what we call an "A+" — truly head of the class.