Union, Connector, Cross, high pressure, 0.75 mm / 0.030 inches through hole with 10-32 screw threads. PEEK, round with an internal "X" flow pattern. ARE-Applied Research brand. 1 EA.
This low dead volume, "Union" is used to connect PEEK or stainless steel tubing with the same connectors on both ends in the high pressures zones of HPLC systems. A "Cross (X)" internal flow pattern is often used to split flow into two or three directions or to combine two or three streams into one.