www.safetyandhealthmagazine.com/articles/foot-warming-insole-2

Foot-warming insole

October 1, 2011
The PolySorb FLOW Warm Insole blends comfort and support with foot-warming technology designed to provide protection against cold weather without overheating. Featuring an ultra-thin foil layer to initially capture natural body heat, the insole implements temperature phase-change material from Outlast Technologies Inc. to absorb, store and release heat as needed.

Spenco Medical Corp.