These are e-liquids which are manufactured with a 50% propylene glycol and 50% vegetable glycerine base. These are suited to most tank types and tend to be the chosen base for the bigger manufacturers as they are more like a one size fits all mix. If you vape with a smaller device or pod system you would be better looking at the 40vg 60pg range or if you love cloud chasing with a sub ohm device take a look at the higher vg based e-liquids.