Colder NS6D22008 Polypropylene Tube Fitting, Insert, Shutoff, In-Line, 3/8" Insert x 1/2" Barb Insert coupler has one or more ribs for creating a tight seal and connects tubing in a straight run Insert coupler on one end and barbed construction on the other end for connecting tubes with different ends Polypropylene for chemical resistance and dimensional stability Working pressure of up to 120 psi Operating temperature range from 32 - 160 degrees F