The letters are a bit small for a single monogram design on a 3" cookie. There are upper case and lower case letters as well as numbers. I can probably fit a 2-3 letters on a 3" cookie. The plastic is food grade with no bad smell. The material is flexible enough to lay flat against the cookie but stiff enough so it doesn't shift when you scrape the icing over it. If you have the right Royal Icing consistency, it works very well. The icing I used was somewhere between medium to stiff consistency. I used my hands - no stencil holder - and it took me 3 cookies to get the hang of it. It would be nice if the plastic was a little more see-through. I had to eyeball it to get the letter on the right spot. I'm looking forward to using them again.