Thrifco Plumbing 6821240 3/4 Inch FHT Swivel Adapter – Black.Compression fittings are among the most common connection style fittings used in drip irrigation systems to connect sections of either 1/2 or 3/4 solid drip irrigation tubing or dripperline. Compression fittings have an internal compression ring that squeezes the outside diameter of the tubing as it is inserted into the fitting. The sharp edge of the ring bites into the soft tubing to prevent the tubing from blowing off the fitting and also creates a water tight seal. Compression fittings are more of a permanent connection and are not recommended for reuse. Once the tubing is inserted into the fitting it is very hard to remove the tubing.