71 Demon

go to the hardware store and ask them for them, they will know what you you are asking for. They have a screw thread on one end to thread in to your fender extension and a 1/4-20 bolt on the other to bolt to the fender.

Just to be safe take the fender extension with you and make sure it screws in. Use JB weld or epoxy to anchor them tight in the extension.