Colorado State University developed and tested a new design for a high flow sampler (HFS) instrument to quantify leaks from natural gas systems. CARB initiated this project to inform and incentivize production of HFS instruments after the only commercially available HFS was no longer in production. CARB’s Greenhouse Gas Emission Standards for Crude Oil and Natural Gas Facilities (Oil and Gas Regulation) includes methane emission rate standards for compressor vent stacks, low bleed natural gas-powered pneumatic devices, and well casing vents, and operators are required to measure emission rates to ensure equipment complies with the flow rate standards. CARB funded this study to identify key required technologies and to develop a working prototype HFS.