Shipping and Heat Packs

This is a ball python specific shipping question, hopefully this is not in the wrong place.

I'm shipping a 2500+g girl out to colorado, where at night it has been maybe 45, and during the day it's about 75. It's probably in the high 50's here at night, 60's during the day.

I have a box with 1" Styrofoam, but I think at this point I need a heat pack. I don't have time to order a reptile one, and I friend recommended I could use something like the glove warmers, does anyone have any advice on which kind to get (8 hour, 12 hour, etc), how to pack them, I know these can get hot and I dont want it burning the snake obviously, etc.

Thanks in advance!
-Tom

The hand warmers don't sustain enough heat for a long enough period of time to be useful for shipping. At a minimum you need a 40hr heat pack.