Product details: Brand: ROCKBROS Color: Black+brown Material: Polyester Weight: 648g (backpack) 98g (brown bag) Capacity: 24 l Size: 28*16*45cm (backpack) 25*16*60cm (brown bag) Features: 2-in-1 design: The ROCKBROS bicycle backpack offers the option of using the brown main backpack and the black outer backpack separately. This gives you the flexibility to choose the right backpack according to your needs. Waterproof material: The interior of the brown backpack is equipped with waterproof material to keep your personal belongings dry. The roll-top design with snap fastener provides additional security and protection from rain. Breathable comfort: Thanks to the three breathable foam mesh inserts on the back, the ROCKBROS bicycle backpack provides good ventilation and shock absorption to prevent overheating. Generous capacity: With a capacity of 24 liters, the backpack offers enough space for your daily needs and is ideal for your outdoor activities. At the same time, the buckle position can be adjusted depending on the bag volume. Adjustable and comfortable straps: The wide shoulder straps of the bicycle backpack (soft foam) distribute the weight evenly and reduce the pressure on your shoulders. In addition, the straps have small storage pockets in which you can keep your cell phone close at hand. Compatible with hydration bladder: The backpack is compatible with a hydration bladder, so you can conveniently drink water on the go. The hydration tube holder allows you to attach the tube to the shoulder strap. (Drinking bag not included)