These are small rare earth magnets - 3/16" rings. 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. This one small ring can easily hold a piece of paper to your fridge. We found these small rings to be very useful for connecting PCBs together. These rings are conductive and can act as a magnetic connector between widgets. You need a way to secure the ring to the PCB (screws and rivets have been shown to work). Sold in single units. Features: * Dimensions: 3/16" od x 1/16" id x 1/16" thick * Tolerances: ±0.002" x ±0.002" x ±0.002" * Material: NdFeB, Grade N42 * Plating/Coating: Ni-Cu-Ni (Nickel) * Magnetization Direction: Axial (Poles on Flat Ends) * Weight: 0.00665 oz. (0.189 g) * Pull Force: 1.48 lbs! * Surface Field: 2275 Gauss * Brmax: 13,200 Gauss * BHmax: 42 MGOe https://elecena.pl/product/745071/magnet-ring-3-16 2008-10-23 https://elecena.pl/product/745071/magnet-ring-3-16 2016-11-25 https://elecena.pl/product/745071/magnet-ring-3-16 2016-11-28 https://elecena.pl/product/745071/magnet-ring-3-16 2016-11-29 https://elecena.pl/product/745071/magnet-ring-3-16 2016-12-09 https://elecena.pl/product/745071/magnet-ring-3-16 2016-12-13 https://elecena.pl/product/745071/magnet-ring-3-16 2017-11-24 https://elecena.pl/product/745071/magnet-ring-3-16 2017-11-28 https://elecena.pl/product/745071/magnet-ring-3-16 2018-05-05 https://elecena.pl/product/745071/magnet-ring-3-16 2018-11-21 https://elecena.pl/product/745071/magnet-ring-3-16 2018-11-27 https://elecena.pl/product/745071/magnet-ring-3-16 2022-02-22 https://elecena.pl/product/745071/magnet-ring-3-16 2025-04-14