Sidekick is the perfect oxygen cylinder tote for any oxygen cylinder user. It is so versatile as it can be used as a roller bag as it has two wheels with two front ‘legs’ to allow it to stand upright. Similar to roller luggage. Wheels roll very easily. This bag can convert to a backpack or shoulder bag with straps to allow ease of movement for those who are more active. The front pocket has a puller that attaches to two zippers to allow ease of slipping a cylinder inside the pouch. Interior of pouch has security straps.to cinch cylinder in place. To convert to a backpack, retract roller handle and extend the padded backpack straps. The bag is triple padded in the back to minimize pressure on user’s back. Bag material is washable and heavy duty. It has a mesh water bottle holder, a large external zipper pocket to carry extra tubing or supplies. Included is an unopened bag of 6 mm green oxygen tubing with 2 standard connectors. 50 ft. (15.2 m) Measurements. 23.5 inches long x 10.5 inches wide at base x 8.5 inches deep and weights 4.75 pounds. It has been lightly used and does not come with warranty Not, for use with liquid systems or portable concentrators. TriMed.com has a chart for cylinder size chart.