Non serrated hex flange bolts have a smooth, non-rotating washer attached that does not bite into the surface it's being mounted to. Their large bearing...

Serrated hex flange bolts have serrated washers attached that distribute pressure and are able to provide sfficient grip onto the material it is being...

Serrated large flange hex flange bolts are made to be driven by a socket or wrench. Their built-in washer distributes the pressure on a wider surface area...