it is 50% nitro "propane" which is very similar in chemical makeup as nitro "methane" not quite as how do you say "stout" but very close. it is a lot cheaper is why companies use it instead.
either way is the point is this additive is a oxygenated fuel and can be very harmful for a engine, or very beneficial depending on your tuning abilities. use it and enjoy it''s benefit, but be safe and don't get greedy.