The pattern is for 2 sizes, large and small. The bags I made were the large ones, but I will probably make a small one for my small travel iron.
I've now used the bag several times and it is so nice not to have to wait for your iron to cool when you are packing up just so you can transport it. The only modification I made to the pattern was in additional to the InsulBright and batting, I also added a layer of teflon material. No particular reason, I just wanted to be double sure.