Complete system of compression fittings and adapters for all tubing connection needs in a low-volume system. Reduces inventory costs; Multi-diameter compression fittings work with a wide range of 1/2" polyethylene tubing sizes (0.630" to 0.669" or 16 mm - 17 mm outside diameter). Adapters swivel for easy installation. Provides increased flexibility; Just three Easy Fit Fittings and five Easy Fit Adapters are needed to make over 160 combinations of connections, accommodating countless installation and maintenance situations.