100 Pack, 1/2", Brass Barb Insert Coupling, For Cross Link Polyethylene Pex Tubing, Use With TV #608-933 Cinch Clamps, Need Cinch Tool TV #608-743 Or Copper Crimp Rings On Cross Link Polyethylene Pex Tubing, After Crimping You Can Immediately Test Each Fitting To Well Over 100 PSI After Crimping, You Can Immediately Test Each Fitting To Well Over 100 PSI, NSF Listed Brass Inserts.