The Onyx II, is the sealed version of the 2011 Scubalab Testers Choice regulator, the Onyx. With the same attractive finish and outstanding performance as the Onyx regulator, the Onyx II fills the need for those that find themselves in cooler water. The internal structure allows direct airflow through the 1st stage, providing lower turbulence for outstanding performance. Our conical precision high-pressure valve provides much greater reliability and service life compared to conventional designs, while improving responsiveness and performance at all breathing rates. The braided LP hose provides high flow and tremendous abrasion resistance while having great flexibility. The compact exhaust tee, advanced black satin chrome finish and light weight construction give the Onyx II a beautiful presence. An anodized aluminum heat sink on the 2nd stage along with the external diaphragm on the 1st stage improves the cold water performance of the Onyx II regulator. Work of breathing at heavy* demand: 0.95 Joule/Liter *198 (60M) depth, 750 psi inlet, 62.5 RMV (liters per minute respiratory volume) Like all Zeagle regulators, The Onyx II comes factory ready for use with EAN/ NITROX to 40% O2.