4.5" wide 10mil Nomex Paper.    I don't cut pieces until you order them, so if you order more than 1, it will come in a continuous piece.     

The roll is hand cut to the 4.5" width, guaranteed minimum width of 4.3".   If you need a guaranteed minimum of 4.5", please ask, I can cut to 4.75" wide. 

Other widths available, please ask if you don't see what you are looking for.