SPECIAL ORDER ITEM. Review Returns Policy before purchase. A Barbed Tee is a T-shaped plumbing fitting used to split or join flow in flexible tubing systems, most commonly in PEX, polyethylene, vinyl, or irrigation tubing. The barbs grip the inside of flexible tubing, and when secured with a crimp ring, clamp ring, or hose clamp, they form a tight, leak-resistant mechanical seal without requiring threads, soldering, or solvent welding.