10/30/50Pcs Strong Countersunk Ring Magnets Hole 5mm Rare Earth Neodymium 25*3mm
Countersunk Hole Size: 5 mm. Material: Neodymium Iron Boron. Made of neodymium iron boron material, these magnets are plated in nickel-copper-nickel for a smooth, shiny and corrosion resistant surface.