These little bags are insulated with that thermal stuff, the kind with the silver backing...I bought mine at Joann Fabrics. There are two different versions, but I knew from the start I wanted to make this rounded version. The fabric was calling my name over the internet, it's Snappy Snacks by Nicole's prints for Alexander Henry. Isn't just too cute?!
Phone pics of the vinyl application:
I also wanted to stress how helpful these little red clips were in this project---I usually use them for my quilt binding....but I saw Sara had them in the pattern pictures, so I thought I'd try it. Good Lord did they help a LOT!!!! WAY better than pinning, especially the tight little corners and multiple layers that this pattern has. Great tip Sara!
Picture of the assembly process with all the clips helping me out: (inside out).