A simple reef rack I designed for my reeftank.
I use 22mm x 6mm isolated magnets for this one.
Link to a german shop: https://www.maqna.de/gummierter-neodym-scheibenmagnet-22x6mm-vernickelt-grade-n42
The hole dimenson for the frags is 13,5 mm
I printed mine without supports in PETG