I had to google these since I hadn't heard of them yet. Wow! But @ $300 they're a bit pricey. I wear Sidis but replace the insoles as soon as I get them so probably wouldn't like these.

http://www.cippsites.com/Merchant4/m...ore_Code=ANGLE

My solution for cold fee is to use the little chemical heatpacks you use in ski boots. If you get them bulk on sale they're about $1/pair.