Dogline Side Utility Bags for Unimax Harness Service Dog First Aid Kit Medical Alert Made of lightweight nylon material with zipper closures. Velcro attachment provides easy take on and take off. Bags are available in black or red and are sold in a set of 2. Bags feature space for removable velcro patches (sold separately), and offer a large main storage area and a side pocket for smaller items. Size Small/Medium corresponds with sizes Small and Medium Unimax Harnesses. Size Large/Extra Large corresponds with sizes Large and Extra Large Unimax Harnesses.