What does it mean?
GSM stands for 'Grams per Square Metre', it is how paper weight/thickness is measured.
The higher the number the heavier the paper/card/board, e.g. office copier paper would be 80gsm, magazine covers are 180-250gsm and good quality business cards are 340-400gsm.
For self-adhesive vinyl we show the weight of the vinyl and the backing paper combined in GSM. Once the backing paper is removed, all of our vinyl are between 100-180 microns in thickness.