This is the Apeks AT20 Scuba Diving Regulator Features: AT20 Predecessor to XTX20 Represents an Excellent Value Ideal Entry-Level Regulatorv Can Spoil Divers In-a-Hurry High-Performance Regulator Designed for Water Temps Above 50°F (10°C) Nitrox Ready Up to 40% O2 Out-of-the-Box First Stage: APEXS AT20 Balanced Diaphragm Design Consistent Performance from Start of Dive Until End of Dive LP Ports: 4 Port 3/8 UNF Thread HP Ports: 1 Port 7/16" UNF Thread Body: Marine Brass, w/Chrome Finish Second Stage: APEXS AT20 Pneumatically-Balanced Second Stage Smooth, Easy Breathing Large Purge Button, Easy to Operate w/Thick Gloves Integrated Venturi Control: Provides Performance Boost at Depth Prevents Unwanted Free-Flow at Surface Extremely Efficient Exhaust Valve Improves Breathing Performance Compact, Integrated Exhaust Tee The AT20 is the predecessor to the XTX20. We brought it back to the Apeks line up because it represents an excellent value. This is an ideal entry-level regulator that can spoil divers in a hurry."