The 3-640622-4: The female socket contacts are tin-plated at 80.0 µin (2.03 µm), a thickness that handles moderate environments without the cost of gold. The blue colour is a visual aid on the assembly line — you can spot the 4-position part at a glance among other MTA-100 counts.
Termination and Wiring
This is an IDC (insulation displacement) termination — you push the wire into the slot and the contact cuts through the insulation to make the connection. No crimp tool, no stripping, no solder. It works with 26 AWG wire, either discrete strands or ribbon cable. The free-hanging, right-angle mount means the cable exits at a right angle to the connector body, which helps route the harness flat against a panel or along a board edge. The feed-through feature (listed in the spec) lets you daisy-chain multiple receptacles on the same wire run without cutting the cable — useful for a simple multi-drop signal bus.