The Parker Hannifin 71918 5/8" x 1/2" Fast-Tite Compression Style Plastic Fitting for Pulsar Infinity and CCH Endurance Systems is a compression-style fitting that installs in seconds without tools and provides a tight, sure, leak proof seal without clamps or adjustments. A unique grab ring for tube retention, coupled with a nitrile o-ring, creates a positive seal and assures good tube retention with only hand tight assembly. This product is designed for use with soft metal, glass tubing and compatible pool maintenance systems.