The women s crosswind 24 rucksack from jack wolfskin is a classically designed lightweight and durable 24 litre outdoors bag that is packed with the features you normally find on a larger rucksack making it ideal for cycling and fantastic long days hiking out in the beautiful outdoors the acs air control system carry system on this bag allows constant air flow thanks to the reduced contact surface and gap between the pack and your back that is created by the fibreglass and flexible plastic frame