The MOA hanging kit is designed to hang your two hole targets from a stand, allowing the target to swing freely. Free swinging targets tend to hold up much better long term. Each MOA hanging kit includes:
Hanging kits are considered wear parts, and will be damaged by pistol and rifle fire. Each kit includes two spare sets of nuts, bolts, and washers (six sets total). There's nothing proprietary here, feel free to pick up spare parts at your local hardware store. On the other hand, you're going to have a hard time beating this price unless you're buying in bulk or salvaging hardware. Be sure to use carriage bolts if you pick up your parts locally, so they'll sit flush in the square holes.
Also, if you are ordering your hang kits with targets, MOA may upgrade you to 1/2" hardware to match your targets, assuming they have 1/2" holes.