Ride the Vespa scooter to work (13 miles) almost everyday, even in the winter of Northern California (SF Bay area) and need warm hands.  Right now I do NOT have the scooter outfitted with hand wind blockers but that's next.  Wanted to try out the gloves.

I layer them, first off.  And found that if you get them going at least 3 mins before you hit the outdoor cold temps they will work much better.

I got rechargable batteries for them...because they do drain the batteries.

The battery pack isn't "slim line" because the battery pack is a tad large...size of an old school (1990s) pager.

Read the other reviews either here or on other sites for how people get the best out of the Warmawear Battery Heated Glove Liners.

I have a size 6 1/2-7 glove (if you're in health care you get this size) or what most people consider a small-medium. And I got the small/medium...fits fine.

UPDATE:  After a winter of trying to find the best warm hands situation...I put out the money for thinsulate leather gloves.  Might combine them with these battery powered numbers on the coldest days but the battery issue became a major headache even with rechargeables.

If they get wet...takes some time to dry them out.  I tend to unplug them during times of none use.