I found these posted on a website for outdoor gear after some googling. They are basicaly a portable footwear dryer that requires no batteries, 110vt, or even propane.
I have found many outlets selling them in the $20-30 price range.
One exampleRead this unbelievable test !!I think the stuff pads are made with a silicone dessicant of some type.
If someone here has these, I would love to hear about it.