Handy dandy super stainless steel band clamps for racks, lights, whatever you want to bolt to your frame where there's no frame braze-on. 

Tiny size works on most steel seatstays and right at the bottom of the fork, near the drop out, if you're unlucky enough to not have a fork with eyelets.   Note: there are several sizes of "tiny size clamps"; all are very similar in size, we don't differentiate between the tiny sizes but yes we do at least match the exact sizes with each other.

Huge size works on most steel forks above the fork rake curve and on handlebars.

Medium size works on things in between.

Rubber shim can be cut down a bit or if the clamp diameter is a little big even with the rubber shim, just wrap some scrap inner tube, electrical tape, or bar tape around the frame until it's tight enough.

Sold as a pair.