Unlike standard bolt-on applications, the rear end side is pre-installed with a dedicated mount in the dowel hole for easy and quick installation by attaching the belt to the seat tube. Compatible with QL1/2.1/3.1/TOPLOCK systems, so you can attach the rear carrier basket and pannier bag at the same time. OR-F78104 26" / 28" / JAN Code: 4013051054614, Black, 12.8 oz (580 g) / 33.1 / Top Lock Compatible, Aluminum