Enables ready?? convenient access to O2 cylinder wrench</br>Cable/chain is extremely durable</br>Attaches easily to regulator screw</br>Never Lose Your Wrench!</br></br>Product Description</br></br>For use with Post Valve-Style Oxygen Cylinders including D & E Tanks. -Enables ready?? convenient access to O2 cylinder wrench-Cable/chain is extremely durable-Attaches easily to regulator screw.</br><br/>http://www.amazon.com/gp/product/B00GL8C8GO