Variable volume allows for adjustment from 14-18L with a quick zip expansion; Padded and breathable EVA back reduces heat and cushions any pressure; Shoulder straps are padded and ventilated; Vest inspired pack straps with three layer chest pocketry to hold trail essentials such as water, phone, sunglasses or keys; Adjustable sternum strap expands for when you're breathing heavy; Trekking pole connections; Hydration / Soft flasks NOT included