GSM is a measurement of the weight of paper or card rather than a measurement of thickness, therefore it is not applicable to apply the same formula to magnetic paper to calculate the GSM as you would traditional mediums.
The Pull Force listed for each magnet is based on lifting 10mm thick steel from a horizontal surface. Magnets on a vertical surface (of 10mm thick steel) are generally able to hold around only 30% of the pull force listed in the product description. This is due to the effects of gravity and the lack of friction between the surface and the shiny magnet. Read More
