Our Seatpacks are meant for light, large-volume items like a sleeping bag, tarp, and clothes. They feel solid on the bumpy stuff (even loaded up) because they have a 360 internal plastic frame that holds their shape. Rugged metal cam buckles means secure, no-slip connection points. Durable, water-resistant construction. Good thigh clearance with room to get behind the saddle. These are streamlined workhorses with one strap for compression and extra gear. They come in two sizes (10.5L and 16L) depending on how much space you need and what your bike fits. The 10.5L also works well with a dropper post!