The reserve cartridge is a premium offering from O.penvape. Exceptionally pure, these reserve cartridges have highly concentrated pure cannabis oil that is triple refined over low head to preserve the batch-specific and strain-specific terpenes. This 420mg pure oil cartridge from O.penVape’s Reserve line of cartridges was not cut with any additives like propylene glycol or ethylene glycol. This is 420 mg’s of pure, strong, wonderful cannabis oil. This cartridge is sized to fit a 510 threaded battery, which is the universal size and will fit the one you already have. You can also purchase a battery from TrySunshine if you need one. The oil in this cartridge has been extracted in a Berkeley lab from the Gobstopper strain. For the true cannaseur, reserve is simply the best.