Pyrex glass prevents leaching of oils into the tank material (unlike plastic tanks which can absorb up to 30% of THC within a month). Easy fill with no mess, 0.5ml capacity. Extra ariflow passages for a smooth draw. Top airflow no-leak design. Designed for thick oils. For thinner oils use the Horizon kits. For very thin oils, use the Phantom-X vaping kits. Single-use design.