That's what I thought, but the Mugen I received was a counterfeit (labeled for my 'Driod Pro'. Ordered thru official Mugen link based on repuation and positive reviews - what I discovered is that there is no central Mugen store - they are all independent distributors who can charge whatever they want. Mine came from Asia (this was not obvious until after clicking 'buy"), and was a fake. My phone did not recognize it at times... it would not hold a charge... all the badness that could be, was, short of explosion or fire. I WAS able to return for a refund of purchase price, minus shipping.
I would be a bit cautious. I have the Verizon extended battery for the Trophy, and it works perfectly... does what I expected. I use standard battery on days when I will be near a charger, and extended when I won't. With extended, I never worry about running out of juice before I can recharge. Love it.