What this 6-position MTA-156 IDC receptacle is for
The 0.156" (3.96mm) pitch gives enough spacing for 18 AWG wire without crowding the IDC slot. The closed-end back wall keeps header pins from poking through the back of the housing, which matters when the connector sits against a panel or inside a tight enclosure.
Termination and wiring — IDC with 18 AWG
No crimp tool or terminal is needed on the wire side.
If this connector is going into a panel that gets opened for service (disconnect and reconnect several times over the equipment life), the gold plating is the right call. Tin-plated MTA-156 receptacles exist, but they are for one-time or low-cycle connections; this one is built for field-service duty.
Locking and retention
The fastening type is a locking ramp — a molded latch on the receptacle that snaps over the header's locking ramp. The locking ramp is the only retention — no screw locks or additional hardware.