This little bit of neoprene seals the bottom of your helmet to
your neck - cuts drafts and noise. Pity you can't see it because
it's black and so is the helmet lining in the picture.
Get it from Proline Sports in England.
Gorex Electric VestWorks. Simple. No nichrome wiring to break. No hot spots. Includes a real temperature regulator. Get it from At-Last.