Easy to assemble, simply slide the ferrule over the tubing and finger tighten the nut. No need to flange your PTFE tubing! The 1/16" ferrule and nut are rated at 1000 psi; the 1/8" ferrule and nut are rated at 500 psi. Feature 1/4-28 threads. Flangeless Fittings are easy to assemble. Slide the ferrule over the tubing and finger tighten the nut. Excellent chemical resistance. 1/8" fittings are rated to 500 psi; 1/16" fittings are rated to 1000 psi. All fittings feature 1/4-28 threads.