This line of Chokes has a manually operated needle or stem, which provides variable flow rates. Moreover, a visual indicator provides an indication of approximate orifice size for flow rate calculations. Chokes may be ordered in both positive and adjustable models. Each model utilizes a hammer lug type connection which facilitates the quick changing of flow beans and trims. Neeco designed the H2N in accordance with API-6A and NACE MR-0175 for H2S Service.