PARFLEX POLYETHYLENE TUBING Flexible, low density polyethylene tubing. Applications include pneumatic lines, pitot lines, and instrumentation. Use nylon inserts with nylon fittings. 1/4″ OD may also be used with brass fittings. Working pressure: 120 psi. Minimum burst pressure: 480 psi. Operating temperature: -80 ºF to +150 ºF.