Igloo 16qt cooler 2 compartment box

I'm a mailman and use an igloo 16qt insulated cooler at work. I have 6 20oz flip top bottles of water in in and wanted a way to keep them from sliding around as well as making space to hold my medications and a water soaked hand towel, so I made a simple box with two sections to keep the bottles from sliding around, thick enough that the weight of the bottles would not keep breaking the box (a problem I had with upsized simple boxes that were just one layer thick) This is a simple box with two sections and a wall thickness of roughly 3mm. It's made for strenght, and i whipped it up quick and likely did not get the negative spaces in the cube perfectly centered, but it works. The reason I lay the bottles on their side is because I live and work in South Florida and even with an insulated cooler, I still wanted to have one more layer of foam over the bottles to keep them cool for 6-8 hours on the street in a 110-140 degree truck. It's not perfect but it works. Feel free to mo