PEEK (polyetheretherketone) fingertight fitting are convenient, inert, and bio-compatible. Use these fittings with 1/16 inch O.D. PEEK, stainless steel, titanium, Tefzel, or PTFE tubing. PEEK fittings are compatible with all HPLC solvents (avoid concentrated sulfuric and nitric acids), and can be used at temperatures to 150 °C. Unlike stainless steel ferrules, PEEK ferrules do not permanently lock into place on the tubing. This allows you to interchange fittings with tubing and columns, from mnaufacturer to manufacturer (e.g., from Agilent to Waters), and still form a zero deal volume, leak-free connection. All fittings in this section can be used with internal fittings provided by most major suppliers. TWO-PIECE FINGERTIGHT FITTINGS Our original Two-Piece Fingertight Fittings were designed exclusively for 1/16" OD tubing. We now offer optional ferrules for connecting 1/32" OD and 190μm OD tubing with any Fingertight nut on this page. Our M215 Conductive Perfluoroelastomer Ferrule is designed for mass spectrometer electrospray applications. For more information on this product, please turn to page 28. To order, please follow these guidelines: 1/16" OD tubing select the desired nut, which comes complete with the appropriate ferrule. Or, order the optional F142N Ferrule, along with the desired nut by replacing the [x" at the end of its product number with [01". For instance, if you want an F200 Nut, order F20001, not F200x. Please Note: [01" denotes a single nut without the ferrule. 1/32" OD tubing select the F113 Ferrule. Order the desired nut by replacing the [x" at the end of its product number with [01", as described above. 190μm OD tubing select the F148 Ferrule. Order the desired nut by replacing the [x" at the end of its product number with [01", as described above. 360-510μm OD tubing for electrospray applications, choose the M215 Conductive Ferrule. Order the desired nut by replacing the [x" at the end of its product number with [01", as described above.