Advanced Nitrox?
While this level of training can be done using single tanks with a Y or H valve, I teach it only with double tanks. I believe that at this level of training, the student should make the commitment to purchasing the gear required to minimize risk while diving in caves. Each student must have two complete regulators, one primary and one backup. A decompression stage bottle and regulator is also needed. At least one guideline reel and one liftbag is required, two reels and liftbags are strongly recommended.
