It runs a 94mm bolt pattern, which allows you the option of running a smaller chainring than your standard four bolt MTB cranks. Plus it makes them look classic. They use a JIS square taper BB like the ones IRD sells. Works good and don't cost too much. Also having wide range of spindle widths available will help you dial in your chain line. I've been grinding up and down the hills of SF on this set and they feel stiff as can be.
This is great if you're trying to maximize your clearance or if you're running a 1x9/10spd drive train and want to give yourself some room on the low end for climbing. They will be sold crank arms and rings separately so you'll have a few gearing options to choose from. Since the crank arms taper very subtly outward you can get a super low Q-factor, even if you use a wider BB. They're designed for a single ring mounted on the outside of the spider, but you can mount a second ring on the inside if you want to run a Dingle Speed drivetrain. Just get longer chainring bolts.
I'm running them with a 30x16t gearing right now. These won't be available for a couple months, but when they arrive they'll be for sale through the Soma and IRD web stores and via your LBS.
In case you were wondering what a Mjölnir is and how to pronounce it, you can find more info here.
I think it's a pretty apt name for these puppies.