Doesn't last.
Bought one year ago today.  I've used them 5-6 times.  The first 3 times they worked well.  Though they didn't hold a charge for long after charged.  Batteries dead overnight when not in use.  Now the one insole has stopped working completely.  For the short time that the did work they worked well and kept my feet warm.  But not worth it for 3 uses.
Rating: 1 stars