Meets NACE standard MR-01-75 for resistance to sulfide stress cracking. All 316 SST parts are RC 22 or less, meeting safety requirements in petroleum and gas production, pipeline, service and offshore drilling where sour fluid environments can cause sulfide stress cracking. Kerotest/Marsh “N” Series Needle Valves are used in processing plants, oil and gas production, hydraulic and pneumatic equipment, testing labs—anywhere the flow of fluid must be carefully regulated.