I purchased the backpack/vest from a specialist retailer on May 7, 2026. It is size M/L. The manufacturer recommends it for a chest circumference of 95-105 cm. During the first real test (a 5 km run), it turned out to be too big for me, so I bought the smaller size. My chest circumference is 91/92 cm; I thought the larger vest would be more comfortable, but when running, a tighter fit is better. Therefore, I am selling this one. Apart from that one short test run, it is unused and new. All accessories are included, including a whistle, a waterproof bag, spare elastic bands, 2 soft flasks, and ...