The John guest 1/4" OD x 9/16-24unef (3/8" compression) push-to-connect female connector (10-pack) fittings are manufactured from White polypropylene and equipped with epdm o-rings utilizing John guest's push-fit technology to make easy, reliable, leak-free connections. They have been developed to satisfy the compatibility needs for a wide range of applications and can be used on plastic or soft copper tubing. To make a connection, the tube is simply pushed in by hand; the unique John guest collet locking system holds the tubing firmly in place. Disconnection is just as easy and requires no special tools.