This a magnet holder to glue magnets on miniature bases,
Designed for games workshop bases. but work with any "hollow" base
It as an interior space of 10mm diameter and depth 1.6 mm
I used it with one or two of this magets: https://www.supermagnete.de/eng/disc-magnets-neodymium/disc-magnet-10mm-0.6mm_S-10-0.6-N depending on the strength i need.
The first layer as some holes on it to increase glue addesion, same for the interior to stick to the part as much a posible and avoid the magnet geting ripped off