our AFE shop has a drawer full of them (well, they used to, but since we all use them, they're all installed on our battery packs). Anywhoo, the takaway for you is that it's a kit that AFE needs to acquire, so talk to them. Also check their stash of battery packs, they may already be installed on a spare set hiding in a drawer.
BTW, the bags are not authorized, only the screw-in battery pack-conformal weights are.