Compression-type tube fittings are an excellent choice for most hydraulic power-workholding applications. Compression fittings are designed to secure heavy-wall tubing using a bite-type ferrule and compression nut. The 5/16" nominal tubing size that we recommend provides an ideal balance of flow capacity, small fitting size, and tubing configurability. These fittings accept our standard 5/16" O.D. tubing, as well as Fixture Hose and Heavy-Duty Hose with compression-type tube ends.