A couple of signs to mark J-cup locations for bench,curl and squat exercises. Example printed in PLA, but any material will work. There are two countersunk holes in the back for the magnets at this link.

https://www.amazon.com/gp/product/B098WP6V4B/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

The rack pictured is a PRX Profile power rack, but they should fit most racks.