Octopus (alternate air source)

An octopus is a secondary regulator used for emergency air sharing. Divers use this device when a buddy runs out of gas or experiences a malfunction. Most rental kits in Koh Tao include one as standard gear. You will typically find it attached to the second stage of your regulator set. It stays tucked near your chest so you can grab it quickly.

Keep it visible. I once saw a diver struggle because his octopus was buried deep inside a BCD pocket during a 22 m descent in Cebu. This delay creates panic. Always check that your octopus is easily accessible before you enter the water. Ensure the yellow color is bright and easy to spot in low visibility. This simple habit saves lives.