D-Alpha Tocopheryl Acetate 98% USP FCC - This is the higher quality more stable esterified version of vitamin E that will have longer shelf life as it is less susceptible to oxidation than alpha-tocopherol.   This is also the D isomer which is what is more usable by the human body.  The lower quality synthetic vitamin E oils are a 50/50 mixture of L and D forms and not as potent as the pure D.