I made these pins for my laser engraver. The small pins are for 3mm thick material, the large pins have different distances: 2mm, 3mm, 5mm and 10mm.
The small pins contain a 3mm x 6mm round magnet. The larger one needs a 4.5mm x 20mm x 10mm (mine were more like 19x9mm) rectangle magnet. They should be press fit, but a little super glue won't hurt.