Hollis MOD-1 w/o Pod Modular Full-Face Diving MaskKnown simply as the MOD 1, the patented Kirby Morgan two chamber (Mask and POD) design opens up a myriad of configuration possibilities with both Open Circuit systems and Closed Circuit Rebreather systems. Used by United States Marines Combat Divers and Military Dive Teams around the world, Professional Underwater Videography Teams and Scientific Dive Teams, the Kirby Morgan Modular Full Face Mask represents a giant step up in safety, versatility and