Plastic and metal tube fittings connect a wide variety of tubing and piping. Press fittings connect by pressing or crimping. Soldered sweat fittings connect by heating or soldering for a permanent connection. Barbed fittings grab or bite inside tubing creating a tight seal without glues or bonding agents. Solvent CTS fittings are glued to tubing using solvent. Push-to-connect fittings connect tubing without special tools, glue, soldering, or unions. Flare fittings have a tapered end that fits into tubing with a flared end. Compression fittings connect without tools and can be used with PEX and a variety of tubing materials. Quick-disconnect fittings are threadless and connect by hand for systems requiring frequent disconnects and reconnects. Sanitary fittings are used in process lines where cleanliness and sterility are required. Vacuum fittings connect sections of tube in high-vacuum applications.