Magellan Outdoors Castlewood 40L Hydration Backback Blue/Red/Gray Product features: - 40 liters of cargo space - Air vent mesh back system with external frame - Dual stretch side water bottle/equipment packets - Reflective features for visibility - Compression straps - Comes with 2 liter hydration reservoir - Easy clean bladder sleeve - High density closed cell foam shoulder strap with load adjustments - Multiple quick lashing/attachment points - Rain Cover included - Adjustable sternum strap