Product review (5 stars): Really Works!!
So I've had these a week now. And no Frost in my igloo upright 5'8 freezer as of yet. I'm not sure how they did it, but these really work. I purchased 2 packs so I'd have 4,  1 for each shelf and it's just wonderful, I didn't want to have to worry about defrosting all the time and these definitely fit the bill, please note I did not add these after there was already frost, I purchased the freezer brand new and placed these inside once I plugged it in.  I'd definitely recommend buying, I couldn't be happier.