$FCEL if you are day trading, this is not the time for you. If you are long, these large walls indicate a whale is moving money around and trying not to move the price too much. A sell wall often indicates that they want to buy a large amount and are trying to not overpay by blocking smaller investors from moving the price up. It can be the reverse when you see a large by wall. that can indicate they want out and want to keep a price in a range.