Have tried a number of solutions to solve freezing cold hands and all have failed. e.g. heated grips (only warmed my palms not my fingers), 'proper' winter gloves and thermal glove liners (nope - no good on a long-ish ride) and finally found an option which works brilliantly! Keis heated inner gloves - found them for less that £50 (so cheaper than heated grips or decent winter gloves). Easily wired into the battery or can be used with an external battery pack. I went for the former as the extended life battery pack is around £80. Went on a 2 hour ride in close to freezing temperatures and my hands/fingers stayed warm throughout. Wow - a revelation. Downsides: 1. Add a bit of bulk, so make sure your outer gloves will accommodate OK without losing flexibility/control. 2. A bit fiddly plugging everything in, so can be a pain when you stop for petrol etc. But the pros outweigh the cons.
