A. Features: 1. Full brass+chrome plated 2. Easy to read dual scal gauge with screw-on polycarbonate lens for durability. 3. Precision engineered pressure compensated design flowmeter for precise flow. 4. Flowmeter with easy to read tube and virtually unbreakable transparent polycarbonate outer cover for strength and 360 visibility 5. sintered metal inlet filter to trap impurities 6. Reliable external safety relief valve 7. Flush feature permits emergency oxygen to 40 LPM. 8. Please inform inlet and outlet thread when ordering.