These fittings work with all Drip Depot 1/2" poly tubing. Perma-Loc fittings represent our highest quality, most durable and most flexible 1/2" tubing fitting. These fittings can be reused as many times as needed, just unscrew the locking nut and the tubing comes off easily. For residential applications where layouts can change from season to season, Perma-Loc fittings are a great choice. These 1/2" Perma-Loc fittings can be used with any poly tubing with an inside diameter ranging from .590" to .630" (15-16 mm) with a wall thickness between .025 to .050" (.64-1.27 mm).