The ASTM F1554 specification does not specify a default head style for headed anchor bolts. Fasteners such as A325 or A490 require a heavy hex head only, while A307 Grade A headed bolts require a standard size hex head. In contrast, F1554 does not specify what type of head is required for the bolt. Certain situations may call for the anchor bolt to provide more pull out resistance, so a heavy hex head may be useful. For circumstances where a head type is not specified by an engineer for F1554 headed anchor bolts, the contractor should seek consultation from the structural engineer or let the manufacturer provide the most economical head style option.