Brennan PCNY2403-05-05 PBT Push-to-Connect Tube Fitting, Coupler, 5/16" Tube OD Coupler for connecting two pipes in a straight run Accepts nylon and polyurethane tube fittings Made of polybutylene terephthalate (PBT) for resistance to solvents, shrinkage, heat, and impact Working pressure of up to 290 psi Operating temperature ranges from -4 to 175 degrees F