What this TPA does in the Mini-Fit build
The 1727090010 is the 10-position Terminal Position Assurance (TPA) insert for Molex's Mini-Fit TPA2 series, designed to lock into the receptacle housing after the crimp terminals are seated.
Which housing it fits
This TPA is intended for use with Mini-Fit Sigma series receptacles — it slides into the housing face and pushes a secondary lock bar over the terminal retention lances, preventing terminal back-out under vibration or wire pull.