This Brass 3/8" Compression X Compression Valve is manufactured out of forged brass for a durable and reliable fitting. This Valve is a fitting that's designed to be used with aluminum, copper and plastic tubing. Note that this fitting is not ideal for steel tubing, and plastic tubing requires brass or aluminum insert or sleeve. This Brass 3/8" Compression X Compression Valve features threaded nut connections and does not require flaring, soldering or any type of tubing sealant. Its manufactured for use in potable water, instrumentation, hydraulic and pneumatic systems only. When installing compression fittings, be sure to tighten the nuts to the recommended pressure for a connection that is safe and secure. Over tightening will lead to ironing out or washing out the threads and damage the connection.