Large iron nails like those that would have been used in the crucifixion of Jesus Christ.

These nails are based on two documented archaeological finds of human remains that included nails from crucifixions that happened in the Roman Empire in the 1st century, one in Britain and one in Israel.

These are huge nails, 5” long with about a 1” diameter head, and a heavily tapered shank. Shown in the second photo is one of these nails compared to one of my standard 2.5” long nails.

From the limited archaeological evidence available, it seems that four nails may have been used for crucifixions, instead of three, one nail being used to fasten the heel bone to each side of the cross.