SPECIAL ORDER ITEM. Review Returns Policy before purchase. Designed for smaller supply lines, this dual check valve assembly features an intermediate atmospheric vent to prevent backflow in critical systems. It is engineered for use in laboratory equipment, processing tanks, sterilizers, and dairy equipment, and is recommended for boiler feed lines to maintain system integrity when supply pressure drops below system pressure. The assembly is rated for pressures up to 175 psi and temperatures reaching 250 degrees, ensuring reliable operation in demanding plumbing environments. Featuring NPT connections, this unit provides a secure, permanent installation for fluid control applications.