On sub-freezing days, Rapha's Deep Winter Collar helps lock the cold out. The split-front design allows the rider to wear it as a neck gaiter or as a balaclava. The midweight merino wool is breathable, soft against the skin, and quite insulating. It is about twice as expensive as roughly comparable synthetic or wool items from Buff, SmartWool or Patagonia, but those are either neck gaiters or balaclavas, not this two-in-one design.
Testing in the winter of Colorado on mountain rides where the temperature dropped below 20 F, the Deep Winter Collar soon became a treasured piece. We typically wore it as a neck gaiter, covering the neck and chin, and tucking the sides and back under an insulated winter hat. For descents, or into nasty headwind stretches, we would pull the upper portion over our nose, just under the sunglasses. On downhill sections, keeping the mouth covered and breathing through the merino was comfortable and, importantly, didn't cause condensation build up. Covering the mouth while climbing, however, would cause the merino to get wet, and thus cold when the wind blew.
We've tested a variety of full-face balaclavas on cold rides over the winters, and generally find them to be limiting. Even on easy-tempo commutes, if you start to overheat, or if the nose or mouth portion starts to form (or freeze) condensation, your options are either deal with it or pull the whole thing off. With the Deep Winter Collar, being able to just tug the upper portion up or down is a much more sensible approach. It's easy to keep your nose covered but roll the upper portion up to expose enough of your mouth to prevent condensation, or tug the whole upper beneath your mouth – keeping your neck snug and warm the whole time.
The one-size-fits-all Deep Winter Collar runs 9in / 23cm in back, and 13in / 33cm in front, with a 5in / 13cm upper overlapping the 10in / 26cm lower. It has two reflective strips on the back, and is 98 percent merino and two percent elastane. While it's certainly not cheap, it also makes riding on sub-freezing days about 98 percent more enjoyable.