What this 4-position MTA-100 header is for
The gold mating finish (30.0µin) on the square male pins supports repeated mating cycles — useful if the harness gets disconnected during service or rework. The tin-plated post (150.0µin) solders cleanly into a through-hole board. The single-wall shroud provides basic polarization — the plastic wall on one side prevents the receptacle from being installed backwards, but it does not fully enclose the pins. For environments with debris or accidental side-loading, a fully shrouded header offers more protection.