Joe, 23.5% is the nitro content. My LHS ordered a bunch of this for a local heli guy and he bailed on the purchase. I picked up a few gallons to try since it was cheaper than 30% Heli. I can't tell the diff between the 30% and this 23.5% in my tuning but the heat of the summer may make a diff so we'll see. Oil content is still 22%.