The Lowe Alpine AirZone backpack can be extended from 33 litres to 40 for the extra gear you might need to carry. This is ideal for when you struggle to repack your gear once you\'re already out and about.4 season hiking pack from Lowe AlpineAdaptiveFit - adjustable back length and AdaptiveFit hipbelt ensures the perfect fit and hence most comfortable carry.AirZone breathable back system - maximises airflow to keep you fresh during treks.Expandable volume - giving versatile storage options.Stretch hipbelt pockets - for easy access to essentials.Hydration compatible - access beneath lid of pack. Water bladder is stored in an internal pocket.Internal key clip - for safe storage.Internal lid zipped pocket for valuables - SOS instructions printed for emergency situations.Phone compatible harness pocket - made from 3-way stretch material. (Note you may need to protect your phone/GPS will a protective cover)Rain cover - allows pack and contents to remain dry in heavy rain.Easy-access side entry - maximum access whilst expandable volume giving versatile storage options ensuring the contact areas of the back are not dirtied by placing on the ground.Large side stretch mesh pockets - for extra storage.Versatile front elastic stowage cradle - for easy storage of additional items. i.e a wet shell jacket.Unique, patented walking pole \"Tip Gripper\" - poles can be fixed to your pack whether you use them with a rubber end-stopper or just a point.Easy-access zipped front pocket - accommodates standard OS maps,Volume: 33lt+7lt extension = 40lt Weight: 1.47kgLoad Zone: 10-15kg Fabric: N6.6 210D Mini Rip