Ride Free Biker Skull Cap This biker skull cap is entirely trimmed in faux leather. There is a 100% cotton patch on either side of this do rag. Printed on the cotton patches are a skull with ìRide Freeî written below. These durable skull caps are double stitched to ensure that they will last. One size fits most. CKB Products offers great deals every day on our skull caps and other motorcycle accessories.