Adapters are designed to adapt a female connection to another size and or type of connection without the need for additional couplings. Adapters provide the flexibility needed for both large complex systems to simple tube racks. These adapters are used in fluid handling components for the chemical/petrochemical, research, and oil and gas industries. O - Ring adapters are made of various materials like steel and polypropylene. O-ring adapters make a minimum volume connection from the 10-32 or 5/16-24 female threads used on our on/off and prime/purge valves and on some gauges, regulators, and flow controllers to external fittings.