The SMC AS elbow air flow control valve with tamper proof adjusting is made of polybutylene terephthalate (PBT) plastic and nickel-plated brass, and has male National Pipe Taper (NPT) threads with sealant on the inlet port and a push-to-connect tube fitting on the outlet port. The valve body is made of PBT for strength and light weight, and the internal metal parts are made of nickel-plated brass for resistance to corrosion. This valve has NPT threads with polytetrafluoroethylene (PTFE) sealant on the inlet for creating a tighter seal than straight threads, and the push-to-connect fitting on the outlet allows a one-touch connection to nylon, soft nylon, or polyurethane tubing. It is designed to be located downstream of the cylinder for meter-out control. Air flow is set with a special tool (sold separately) to help prevent unwanted adjustments, and there are ten needle rotations for precise manual control of the flow rate. The maximum operating pressure is 145 pounds per square inch (psi), and the ambient and fluid temperature range is 23 to 140 degrees F (-5 to 60 degrees C). Air flow control valves (also called speed controllers) regulate the flow of compressed air into or out of pneumatic cylinders to control the speed of motion of the piston in the cylinder. The valves have an adjustable metering needle and a check valve to control the flow in only one direction. Air entering the valve is blocked by the check valve and forced to pass through the needle valve, and the position of the needle is adjusted to determine the rate of flow. Pneumatic systems with cylinders are used for applications such as truck and train air brakes, air compressors, and tools for mining, manufacturing, and construction. SMC Corporation of America, a U.S. subsidiary of SMC Corporation in Japan, was founded in 1959 in Tokyo. SMC manufactures actuators, valves, airline equipment, connector fittings, electrical products, vacuum products, dryers, temperature control chillers, and a broad range of related accessories. SMC Corporation of America is headquartered in Noblesville, IN, and meets International Organization for Standardization (ISO) 9000:2000 standards.