The 142138-75: Active lifecycle — no obsolescence flag on this line.
Gold body finish and gold centre contact plating resist corrosion across the 500-cycle life.
50 Ohm vs 75 Ohm – Which SMB Jack Fits Your Line
The 142138-75 is a 75 Ohm jack. The sibling 142138 (base number 1421) is the 50 Ohm version — same brass/gold body, same snap-on coupling, same 500-cycle rating, same PTFE dielectric. The impedance is the only selection difference, but it is non-negotiable: a 75 Ohm jack in a 50 Ohm system destroys return loss. Match the impedance to your cable and board trace.