They were scrap from Athens' armor company. They're off of one of the new Odin-suits.
I knwo they look too big, but they're solid. We've wired everything into your spine, so you'll quickly get used to them. The pants and belt are part of the package. Between them and your soldier-boosts, you should have no problem running or jumping.
We haven't done anything permanent, though. It's all neurosockets, so you can take off your boots before bed, and the HMO can still clone you real legs when we get back to a proper hospital.
Or we skip the HMO and just try not to get underfoot.