Spiker Engineering
official vendor
Yeah, you'll be hard-pressed to find high strength flange-head bolts at Lowe's/HD. Ebay, Bolt Depot, BelMetric, or Amazon are your friends
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You will need the longer M12 bolts if you want to retain the tie-down/tow hook brackets. As for the other (SAE) bolts, AOR shipped the bumper attached to the cross-member with these bolts, but they didn't line them up properly and thus cross-threaded the bolts. Ugh. I did have to run a tap through the female threads, and get the new bolts. Hopefully your bumper will be better assembled than mine was.
You will need the longer M12 bolts if you want to retain the tie-down/tow hook brackets. As for the other (SAE) bolts, AOR shipped the bumper attached to the cross-member with these bolts, but they didn't line them up properly and thus cross-threaded the bolts. Ugh. I did have to run a tap through the female threads, and get the new bolts. Hopefully your bumper will be better assembled than mine was.