Magnets are ridiculously strong to the point you have to use two hands to take it off the car, which is exactly what you want for an expensive investment that will be going under a moving vehicle of all places.

Super magnets!!I purchased three boxes (this and two MiniMags - The “2” and the Plus Extra Large) and tested for adhesion and water entry.

Magnets hold strong.

Works exactly as I expected super easy to hide

n’t know how it fell off

n’t stay, lost the