5cm stainless steel tubing with 2 PEEK one-piece fingertight fittings for connecting a guard column holder to the analytical column. Tubing ID 0.007" (0.17mm), PMAX 4,000 psi. For replacement tubing use REST-25817, and for replacement fittings use 220-91522-07. This coupler is a replacement for 220-91209-08.