2 big seams running up the butt so you have to position them just right to be comfortable. And I just found a hole in the crotch, at work, so now I have to walk around the rest of the day holding my sweater down to cover the hole. But it's past the 30 day return window (they've been sitting in my drawer unworn for that long) so I have to either try to fix myself or just throw away. What a waste. I won't be buying from them again.