The No 2400 is electroless nickel plated inside and outside, with all other internal parts of stainless steel. The proprietary stainless steel poppets are finely machined for a metal-to metal seal. Designed to operate in any position, a sensitive spring has been added to close the poppet automatically. Each valve is tested twice for casting integrity and backflow prevention. All valves are 100% American-Made and built to last.