Onset: Takes effect in one to three minutes
Duration: Effects last one to three hours
Most common use: Fast relief for acute issues, or when you don't want to be high for very long. No smoke means it can be used discreetly in more places.
There are basically two forms of this kindler and gentler form of pot-smoking: tabletop and portable. Portable vaporizers are battery operated and often look like electronic cigarettes, thick pens, or an Altoids tin with a mouthpiece. Tabletop models plug in to the wall and vary from wood or plastic boxes with hoses for inhalation to round “Volcano” style metal bases with a bag to collect the vapor and inhale from. All vaporizers heat the marijuana by applying an electric coil to a product chamber holding plant material, oils, or hash. Most tabletop models allow you to adjust the amount of heat applied to the product, most portable “vape-pens” do not. Vape pens tend to be fixed-temperature and tabletop models typically offer a choice of heat ranges.
In all types, the heat is set high enough to activate the cannabinoids, but not high enough to actually burn it. When the material reaches a high enough temperature, the plant oils turn to vapor and can be inhaled. 60-90% of cannabinoids in the original material are present in the vapor, and this translates into measurably higher concentrations of THC in blood of patients using vaporizers. And the lower temperature makes vaporizing easier on the lungs than smoking.