The 1-770996-3: The natural polyamide (PA66) body carries a polarizing key to prevent mis-mating in harness assembly — a practical feature when multiple similar connectors share a panel or cable bundle.
The 13 positions give you a 13-circuit interconnect; the single-row layout keeps the housing narrow along the board edge. The polarizing key on the housing aligns with a corresponding slot on the mating header, so a 13-circuit housing cannot be forced onto a 10-circuit header or vice versa. The natural colour is unpigmented PA66, which is the standard for this series; no colour-coding for keying.
Contacts — Not in the Box
Typical choices are the TE 170262 series (tin-plated, for standard duty) or the 170263 series (gold-plated, for higher mating-cycle or corrosive environments). The crimp termination lets you build custom cable lengths and field-replace individual contacts without replacing the whole housing.
It is RoHS compliant. No official second-source or cross-reference is listed, but the SL-156 series is widely used and the housing mates with standard SL-156 headers from TE and other manufacturers that follow the same interface.