Airsoft Community Europe have published a review of the 5.11 watch cap:
When you have to train or work on those cold mornings a regular cap just isn’t enough, and a warmer solution is needed.
You can use a balaclava, but if you prefer to have your nose and mouth uncovered to breathe easier (especially if your airways are obstructed), or you want to avoid fogging to hit your eyewear then this is perhaps the best solution for you.