Super strong and very light 3 piece crankset made from high quality seamless cro-mo steel with unique bottom bracket system. This special external BB for 3-pcs cranks is compatible with all MTB frames with Euro BB’s. This solution has similar weight to internal Euro BB’s but is a lot more durable thanks to the Spanish BB sealed bearings in external BB cups. The crank axle is drilled, the chromoly arms are seamless & fully heat treated. The chain line is perfect for MTB! Revised great looking square crank arm shape for 2013.