It mates into any standard Multimate III+ cavity, which means it fits the same housings used across TE's industrial and commercial connector families.
The 24-26 AWG range is a tight signal-wire band — common for control circuits, sensor leads, and low-current power lines. Match the wire gauge to the terminal before crimping; the brass base material gives good crimp ductility without work-hardening during the crimp cycle.
Against the 66107-2, the difference is the gold plating thickness: the 66107-4 carries 30.0µin (0.76µm) gold, while the 66107-2 is listed with a different finish grade. For a harness that sees frequent disconnect-reconnect cycles in a corrosive or humid environment, the thicker gold on the 66107-4 is the better choice. The 66107-1 shares the same 24-26 AWG range and stamped construction but differs in plating specification — confirm the finish requirement against your application before substituting.