Recessed Light Trim

To cover up any unsightly gaps, size this appropriately to your application, render and print. Depending on how you intend to attach it you may only need 4-8 magnets per ring (http://www.homedepot.com/p/Magcraft-Rare-Earth-1-8-in-x-1-16-in-Disc-Magnet-100-Pack-NSN0566/204721213), but I put holes for 32 for good measure. You can always reduce those or just skip some. I intend to use a paste laced with iron filings and I haven't tested its effectiveness yet. Also I didn't look up the correct spell