SparkFun COM-08644 Magnet Square – 0.125″
These are very small rare earth magnets – 0.125″ cubed. Composed of Neodymium/Iron/Boron (NdFeB), these magnets are curiously strong and make for a great way to attach tools to a metal workbench, hold small children to a fridge, and as a trigger for reed switches. Don’t let the photo fool you – these are very small magnets.
Activates the reed switch (shown below) at a distance of about 1cm.
Sold in single units.