for at teste svagheder i magnetfeltet

The back side of the arrow magnets are dark gray and magnetic - the front is only slightly magnetic but still strong enough for you to place e

It is not electromagnetism

so they work on whiteboards or metal boards

Power magnet, Skive 25x7 mm. 3M for at teste svagheder iNeodymium magnets Permanent magnets Diameter: 2. 5 cm Height: 0. 7 cm Strength: approx. 12 kg. This magnet has an impressive direct pull of 12 kgs. despite only being 25 x 7 mm. These powerful magnets adhere to all magnetic surfaces. SPECIFICATIONS: Strength: approx. 12,000 gr. Material: NdFeB Magnetisation: N42 Gauss: 12900 13200 (1. 29 1. 32 T) MGOe: 40 42 Max. temperaturee: 80C Surface: nickel plated (Ni Cu Ni)