Ryan K.wrote a review of Castelli Thermoflex Arm Warmer on October 6, 2017
Familiarity: I've used it once or twice and have initial impressions
Fit: Runs small
I have the Thermoflex knee warmers and got these to match. I haven't ridden them in temps below 50 degrees yet, but they seem plenty warm and are comfortable. No falling down at all. I've got long skinny arms, and they're pretty snug and long. I pull them up to my armpits and still go down over my wrists. It works for me, but caution if you've got big or thick arms.