dont know it for sure that it wrinkles, im just affraid of it

what i do know is that the sticker is aluminium, and as you can see on the picture, it is tending to stay "curled"..

this was with the "protection" loose, so maybe you can straight them again in the middle of a thick book
what i do know is that it is easy to insert dents.. so use caution when you are inserting the letters
I can say that i will not enter the letters for you guy's (i also dont have those letter punches

)
i have a sample here, so if you like i can drop it at your place , so you can experimentate with it..
and if thats not enough, i will take 2 or even 3 sheets of this at the supplier, just in case one screws up
