Tool for Cannonade Carbon Si Crankset Used a 3/8" hex key to remove the crank but the outer bolt needs to be tightened separately. Perhaps it's possible to tighten it with the crank off or do I need a special pin type tool. Its a ~2008 Cannondale Synapse Carbon. Hollow shaft running to the opposite crank arm.
You may be able to use a two-pin adjustable BB tool. That search pulls up a lot of images of the tool I'm thinking of, and they're available right down to $5 or so



(from my comment since we haven't got a better answer)