This unique signaling tube is packaged in a trim holster and attaches easily to jacket style BCD's on the right rear BCD overpressure relief valve. Also available for some Back Mounted BCD's, it is diver activated by pulling on the Release Cord which deploys the SMART tube from the holster. Air flows from the BCD into the SMART tube inflating it firmly to it's full 5' length, the SMART tube is now inflated and divers hands are free for other purposes., Check valve keeps air in the SMART Tube even when diver releases air from the BC (to deflate SMART tube after the dive simply hold Release Cord firmly in the "open" position while rolling up SMART tube).