Dial ¼” Poly Tube Insert Adapter (4-Pack)This Compression Insert fitting is made of brass for durable. It can keeps plastic tube from collapsing when tightened and prevent leakage. Primary uses water, gasoline, oil, vacuum and air lines. Brass for corrosion resistance, ductility at high temperatures, and low magnetic permeability It can keeps plastic tube from collapsing when tightened and prevent leakage Primary uses water, gasoline, oil, vacuum and air lines Fittings contain low lead not