The castelli arrivo thermo head thingy castellis head thingys is a neck warmer headband face mask bandana or cap what ever you want it to be it39s made from thermoflex fleece fabric it is perfect for cold winter days thermoflex provides some wind protection while offering excellent insulation thanks to the brushed fleece inside thermoflex is also surprisingly lightweight and stretchy making for unusually comfortable garments castelli arrivo thermo head thingy features