Here are 5 magnets for labeling J-hook placement on a squat rack or power rack. For racks without numbered holes (I have a Titan T3 rack), remembering pin placement can be frustrating, so I decided to make a few magnets to help. These magnets should fit on 3"x3" or 2"x3" uprights.

Print these in two different colors so that the text can be seen. If you use my profile, the letters are already painted. At the beginning of layer 19 with 0.2 mm layer heights, add a pause command in the slicer layer slider. This will enable you to place magnets in the holes so that glue can be entirely avoided (I printed mine with a stainless nozzle on my P1S; hardened nozzles may attract the magnets and cause issues).

For magnets, I used these 1/8" thick, 5/16" diameter magnets from Harbor Freight. There are two magnets per printed piece, so a pack of 10 will produce 5 total labels. You will likely want to print double of every label so that both sides of the rack can be marked.