As the man says, ISIS Bottom bracket. Uses the Same spline pattern as a Shimano Cartridge, though the old tools as mentioned do not fit over, newer 'ISIS' have a larger hole to fit over the axle and a narrower spline bit to get over any preset spacer things.
Try what you have first though.
Mine looks a bit like a larger holed original Shimano one that came with my UN-90 Bottom bracket. Bought it from halfords a few month back in a rush. cheaper online.