Our Flangeless Nut is easy to use, eliminates the need to flange tubing and are reusable. It is constructed with genuine Teflon™ PFA resin making it inert to virtually all chemicals used in an HPLC system. It comes with a 1/4-28 Flat-Bottom port configuration and is for 1/8 OD tubing. It comes in natural color as a single or in a 10 Pack.