Try These
My feet are always cold when we ride, I have tried different boots and socks. What I finally found somethingv that keeps my feet warm they are called Hot Shots. They are wired into your machine and then have inserts that go into my boots, they have an optional temp control that I keep on low 98% of the time. Since I have been using them never have cold feet and since it is wired directly to the battery, I can still keep my warmers on when we are stopped for lunch or whatever. Didn't take hubby long to install. Here is the link:
http://www.foot-heaters.com/
This is from their web site
Electric Boot Warmers
HOT SHOTS thin insole heaters fit inside your boot and plug into your snowmobile's electrical system. Specially designed low temperature "stretch" power cord allows freedom of movement while you are riding.
HOT SHOTS operate on all 12 volt systems capable of operating a headlight. HOT SHOTS are easily installed with hand tools, and fit most all adult size boots. They have low electrical drain of less than one amp each, which means a bright headlight on older snowmobiles that have limited output. HOT SHOT insole heaters stay in your boots and are quickly unplugged when you finish riding.
They are also used on motorcycles, ATV’s, construction equipment, and even by ice fishermen and hunters...anything 12 volt, AC or DC!
NEW DESIGN !
Now, in addition to making the foot heaters more durable, the new design also allows for the heated insoles to be trimmed down to fit several different boot sizes.
The heaters are used intermittently because they are designed to heat up quickly. They work so well that within 8 to 10 minutes, you will turn them off with toasty warm feet. This allows some older snowmobiles with limited electrical output to alternate between heated handlebar grips and HOT SHOTS. And because the heat is generated inside the boot, it is retained for long periods of time.