The bike is the S2. The box is an ammo box I got off Amazon, which I use as storage. I drilled 3 holes on the bottom, found some long screws that match the thread of the bike frame holes, and used washers to keep it in place.

Box on Amazon: Sheffield 12629 Field Box,... https://www.amazon.com/dp/B07B1QH4BQ?ref=ppx_pop_mob_ap_share