This is the Trident Delrin Magnetic Octo Holder with Split Ring to Attach to your BC/BCD Features: Magnetic Octo Holder Made from machined Delrin Air hose is locked in place This is a smart alternative to other quick disconnect octo holders. Strong magnet keeps your safe secondary out of the way yet easily accessible in the event of an emergency. Keep in mind that magnetic tools can affect the performance of analog and digital compass.