Tubing Connector Fittings, High Pressure, One Piece, 1/16", PEEK, Natural, Standard Size Head but a Long Length with 10-32 Screw Threads. Finger Tighten, ARE-Applied Research brand. Additional Info: These all PEEK "Male Nuts" are used to connect PEEK or Stainless Steel tubing in the high pressures zones of HPLC systems. Fitting has a 12mm diameter knurled head, 25mm total length (top to bottom) with an 16mm thread length. The long length is useful when your column or union or detector has a deep threaded fitting and the extra length is needed to seat the tubing properly. The beveled inlet hole helps to make threading the tubing through the fitting easier.