Truvativ Sram Crank Bolt Question

[giverdada]

Hey friends:

I'm isolating in the middle of nowhere (away from all bike shops ever, including the closed ones and open ones), and seem to have lost my crank bolt. It seems that it self-extracted itself. Hard to dig up info on the bike or the part or whatever, and there's a blizzard outside so my phone photos are ****e, but here's what I got:

Bike is 2015 Louis Garneau Elevation HR1, 29er MTB, all stock
(I think) Crank is Truvativ e400, triple
(I think) BB is Powerspline

Hard to find info. Hard to get a part number (I'm not savvy on the search). Hard to figure out. Looks like there are threads inside the spindle for the actual retention of the arm by the bold onto the spindle. Then there are threads inside the crank arm too. Weird. Anyway, if anyone has an encyclopedic knowledge of BBs and their bolts, I'd appreciate the help!

Thank you!