A washboard dirt road descent with two days of gear on the bike is where the POC Ultra Saddle Bag 7L belongs. This waterproof saddle bag uses a TPU outer with welded seams to keep overnight clothing and food dry, and a rigid frame helps it hold its form as the load changes. The roll-top closure sets the volume, so the bag opens to its full 7 liters for a long trip and folds down small when the load is lighter. What Our Gearhead(R) Experts Are Saying:"I rode three days of rough gravel with a loaded bag and never felt it swing or brush my legs. It sits tight behind the saddle, and fastening to both the saddle and the seatpost keeps it from drifting side to side."