Check the listing for details. Mueller B34237 1-3/8” ODF Check Valve – Brass HVAC/R Refrigeration – New in Box. Condition: New. Listed at 125.00 USD. • Model/Part #: B34237. • (1) Mueller B34237 Check Valve. • Manufacturer: Mueller Refrigeration (Mueller Industries, Tennessee, USA). • For use in refrigeration and air-conditioning systems. • Arrow cast into body for easy flow direction identification.