These fasteners are designed to help reduce the possibility of having your flag tangle around your flagpole.
Flagpoles that are mounted at a 45 degree angle experience flag tangling the most, these fasteners will help allow your flag to rotate around the flagpole to make flag tangling less likely.
We have seen a number of "de-tanglers" over the years and as an add-on item these are the best we have seen (at a reasonable price).
The only other solution to prevent a flag from tangling around a pole would be our Spinning flagpoles. The entire top half of those flagpole's spin freely on a bearing to prevent/reduce the chance of the flag wrapping around the pole.
These fasteners are for a 1" diameter pole.
Flagpole Spinning Fasteners