Disclaimer: If there is a gap between the magnet and the magnetic surface

so it fits most cars

so they works best on whiteboards or metal boards

As a secondary test

WHITE metal magneter, 4-pak engros Disclaimer: If there is aStrong white office magnets from Trendform, model WHITE. Perfect for both glass boards and when you need a really strong magnet for the office board. The magnets have an anti slip back so they will stay put on the board and won't slide on a smooth glass board. A bright white magnet will stand out on a black board and be neutral on a whiteboard. Color: White. Strength: approx. 1. 2 kg. Size: 23 x 9 mm. Made with a white metal cap and a strong ferrite