Trying to find a place to put your ponytail when you pull a beanie over your head can be a challenge. Castelli’s Pro Thermal Woman’s Skully has an opening for a ponytail so your hair doesn’t get squished under a cycling helmet. Adding to the comfort, the Thermoflex fabric is cozy and soft. Finally, the stretch and flat raw-cut edges provide a close fitting skully that fits comfortably under your helmet.