The Philmac Rural compression fitting range has been manufactured from high performance advanced thermoplastic materials so it is resistant to corrosion and has the strength and durability to provide a long service life. Philmac Rural inserts are self aligning. Simply bring the insert into the body of the fitting and then tighten the nut with a wrench. As the nut tightens it will draw the insert into the body of the fitting to create the perfect seal every time.