Moulded design.18 ventilation holes.back vents for optimal air circulation.mesh in vents to protect against 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 back stickers.sizes: M (54-58cm) and L (58-61cm).