Usually surprise is an issue--they can jump out of your hands and snap together from a surprising distance before you realize what is happening. They are strong enough that they can fly into each other or to a piece of iron or steel with such velocity that they can break and send sharp 'shrapnel' flying about!
eBay
Hole Very Strong Magnets for Crafts Square With Magnetic Tool Holder Super Magnet Hook Magnetic for Fridge, DIY, Building
Aliexpress UK
Strong Neodymium Magnets 10mm x 3mm - N35. N35 High Grade Neodymium Magnets. Neodymium magnets are currently the most powerful magnets known to man! Details of Neodymium Magnets. Uses for Neodymium Magnets.
eBay
Super Strong Round Magnets Powerful Neodymium Magnets for Fridge, DIY, Building, Scientific, Craft, Office Magnets Super Strong
Aliexpress UK
Ultra-strong neodymium magnets – compact but incredibly powerful. Available in multiple sizes from6mm x 0.75mm up to 30mm x 2mm, these magnets combine powerful rare earth magnetism with apre-applied industrial adhesive backing, making installation quick and hassle-free.
eBay
Super Strong Neodymium Magnets with Hole Dia10mm With M4 Countersunk Ring Hole NdFeB Round N38 Magnet Strong for Fridge DIY
Aliexpress UK
5mm x 2mm N52 Neodymium Disc Magnets ?. Super Strong ?. Strong Magnets 20x10x2 mm N52 grade neodymium block small thin rectangle magnet. Strongest N52 Magnets Strong Various Size 2-30mm DIY, Craft,Small Disc Magnet.
eBay
0.79"(20mm)Super Strong Cup Magnets Neodymium Countersunk Hole Magnet Strong with Screw for Wall Mounting Round MagnetsDIY Imans
Aliexpress UK
Neodymium magnet – the strongest magnet type in the world, also used for industrial magnets. Complete set – 2 x 125 kg pulling force magnet – 20 m dark orange rope with carabiner – screw lock – gloves – dangle hooks.
eBay
10/20/30PCS Strong Neodymium Magnets with Hole Dia10mm With M4Countersunk Ring Hole NdFeB Round N38 Magnet Strong for Fridge DIY
Aliexpress UK
Samarium Cobalt. Grade: N45. Neodymium Blocks. Neodymium Disks / Rods. Neodymium Cubes. Neodymium Rings. Neodymium Spheres. Neodymium - Self Adhesive.
eBay
3x10mm Mini Small Round Magnets 3*10 Powerful Magnets Strong Disc Magnet For Fridge, DIY, Scientific, Craft, 3*10mm 3*10 3x10
Aliexpress UK
They have a high magnetic field strength and have a high coercivity (which makes them magnetically stable). Although magnets can be wonderful toys and highly educational, these are 'adult' toys, andNOT for children.
eBay
10/20x Magnetic Pins Neodymium Magnets Pin Board Magnet For Board Cone Magnets Super Strong Fridge Magnets For Home Storage Tool
Aliexpress UK
Existing Magnet Application: Neodymium Magnets have replaced alnico and ferrite magnets in applications where permanent magnets are required. Higher values indicate stronger magnets and range from N35 up to N52 Grade.
eBay
Super Powerful Magnets Strong Disc Magnets for Fridge, DIY, Building, Scientific, Craft,Refrigerator Magnet, 5x2 8x2 10x2 10x3
Aliexpress UK