They have a flat base and are not as pointed as fids.
Some people mistake these for fids but a fid is a different animal. Grommet horns are used to form grommets on sails, tarps and lifeboat covers. They have a flat base and are not as pointed as fids. You don't often see them in use as they are more work than metal grommets and require skill. But I still sell these old, unused horns and have sent some to traditional sailing ships and to sailmakers. They are 24 inches tall and taper to 3 1/2 inches at the base.