Carbon dioxide (CO2) is a supercritical fluid, meaning it converts into a liquid form when pressurized. CO2 extraction uses carbon dioxide, in liquid form, as the extraction solvent. Like BHO, CO2 is used to strip out different elements in a botanical plant to create pure oil. When at or above the critical point for CO2, the gas becomes a liquid. With the case of botanical plant extraction, the solvent is pushed through the plant material at such a high pressure separating the plant from the purest essence of the bud. The end product is transparent amber oil.