What is the mil (thickness) of your stickers?
Our custom stickers are approximately 15.4 mil (380 microns) in thickness (including the liner) which is about as thick as a playing card.
Keep in mind that the term mil is not short for millimeter. Mil is form of measurement commonly used in manufacturing to specify thickness. It's equivalent to 1/1000 of an inch. You can read more about using mil as a form of measurement on Wikipedia.