Made with durability in mind and to be easy to mount, the Roaster 2 carrier by Birzman is waterproof, reliable and keeps your spare tubes and other smaller essentials safe and secure on every journey.Held in place by a pair of Velcro straps, this compact bags sits under your saddle for ultimate, low-profile convenience. This polyester pack features reflective straps that keep you visible in low light situations and is an excellent addition to any road or MTB ride. Specification: Material: 300D Polyester (water repellent) with reflective straps.,Size: Roadster I -13 x 7 x 4cm, Roadster II - 15 x 8 x 5cm,Capacity:Roadster I - 0.3L, Roadster II - 0.4L.