The Zefal Z Adventure R17 Waterproof Saddle Bag is designed for cyclists who need to carry gear without a rear rack. It attaches to seat rails and the seat post with self-adhesive straps, ensuring optimal weight distribution. The bag is adjustable from 8 to 17 liters and features anti-tear material on the base for durability. It includes reflective strips, attachment loops for lights, and waterproofing to keep gear safe and dry, making it a versatile and reliable choice for long cycling journeys.