Molded design.18 ventilation holes.Back vents for optimal air circulation.Mesh in vents to protect from insects.Adjustable straps for a perfect, comfortable fit on the head.TwistClose tightening system easily adjustable with one hand.Washable antibacterial linings.Removable label for easy use for mountain biking and road riding.Reflective stickers on back.Sizes: M (54-58cm) and L (58-61cm).