The Ekoi Heat Concept gloves include heating elements to keep your fingers warm. These are powered by two thin battery packs in each glove that fit into a sleeve inside the underside of the cuff. A cable with a small plug connects them to the heating elements. Unfortunately, you can feel the batteries digging into your wrists while riding despite them having rounded edges.
Heat output is controlled using a small square button on the top of the glove. Give it a long push and it turns on, while shorter pushes cause the heating to cycle through four different target temperatures, between 25°C and 40°C. The level of heat selected is indicated by the color of the button. Battery life is around two hours at the highest setting; five hours on the lowest.
The gloves themselves are very well padded with a breathable waterproof membrane, although Ekoi still says that you should switch the heating off in heavy rain. Ekoi also advises against washing them. If you plan to ride in -20°C they might be worth considering. But in the UK the cons probably outweigh the pros.