Neodymium magnets:
 
Older Pro Models use round 20 mm diameter, 2 mm thick magnets.
 
Octagonal magnets used for Pro X and Raptor modesl.
 
Fulcrum uses a rectangular magnet with oval shaped hole.
 
Older Pro models use the circular 20 mm diameter magnets
 
Each Set will contain 3 magnets. Lightning Sony will have 6 magnets.
 
Lightning Attachments use 10 mm square magnets:
Bose QC35/45 uses 2 magnets 
Sony XM4/5 uses 4 magnets