From Ron's Bikes:
The classique Italian made pro tour cycling cap to fit starched and aluft atop your hairs, or snugged beneath your hard hat. Natural cotton feel and finish, although it’s 65 percent polyester. So Italian.
Elastic back, one size fits most. If you have a massive head, you can cut out the elastic in the back very easily. That’s what I do half the time for the ones I wear under my helmet.
Machine washable, hang dry! If you put this cap in the dryer it will fit a toddler.