Tris has had a bit of a phonetic breakdown lol.
To clarify they are lag not rag bolts, American name and it’s a misnomer as they have a screw thread not a bolt thread, in this country they are more commonly known as Coach screws - they have a hex head, different again from Coach bolts which have a domed head with a short square shaft underneath which is hammered into timber preventing the bolt from turning.
Ian