I do not know how I survived without it before!! It is advertised as a cooling layer, and it is doing it great - but I also found that having it under the jersey making an early morning start at 6am a bit more comfortable. It provides just that tiny bit of insulation to feel good. Priceless.
This was my first purchase from BOC , just right fitting , great quality, Worn it on my ride love it . Thankyou 👍