These ARE-Applied Research brand HPLC column couplers are actually unions (cat# 47450-01, 47450-02, 47450-03, or 47450-04) and are standard HPLC items that if installed properly while using standard temperatures and normal HPLC solvents, they should be able to withstand pressures up to 6,000 psi.
Click HERE for column coupler ordering information and pictures.