1. Identify what the retention feature retains
Connector retention is ambiguous unless the object being held is named. A feature can concern terminals within a housing, while another concerns the mating connector halves. Molex's contact-retention explanation distinguishes these levels. For a seller, that distinction resolves what an accessory description is actually about before the item is grouped under connector parts. A record referring to a terminal-retention item should not become a claim about how the complete plug and receptacle stay together, simply because both descriptions use the word lock.
Use the retained object to separate a TPA-related line from a housing or contact line. The housing provides the product context, the terminal is the retained item and the secondary feature has its documented retention role. These names do not represent interchangeable sale units. A loose part associated with a connector family should retain its own supported identity; the appearance of an accessory beside a housing does not establish that the offer includes both or that the loose part has the role assumed by an older warehouse nickname.
2. Keep primary and secondary terminal retention distinct
Molex discusses primary terminal lances and secondary TPA features as terminal-level retention. Preserve that relationship instead of reducing both to a single housing-lock field. Primary and secondary describe different parts of the retention explanation; the secondary feature does not replace the terminal, and calling it TPA does not make it a complete connector. This functional distinction is the technical addition to the existing mating-pair guide, which concentrates on identifying the deliverable, counterpart and applicable interface documents.
A TPA feature also should not be confused with a mating key. Keying and polarisation concern the mating relationship, while the terminal-retention discussion concerns the contacts within the housing. Keeping those functions separate lets the recipient ask the correct question about an unidentified accessory. A colour or shape that resembles another locking item is only an identification lead. This article does not infer an installation sequence, a physical contact position or a force result from the primary-versus-secondary terminology.
3. Preserve implementation and inclusion boundaries
Molex notes that TPA implementations vary. That matters when an inventory system treats every TPA as a loose accessory. A functional name does not, by itself, establish whether the actual product implements the feature as a separately supplied piece or within another supplied item. Retain the exact product's own description and the evidence of what the seller is offering. Do not turn a general explanation of terminal position assurance into a rule that all connector families package or supply the feature in the same way.
An accessory photograph also leaves inclusion and applicability unresolved. A picture can show the item presented, but cannot establish that every housing in the group includes it or that a similar-looking loose part is appropriate for those housings. Keep a documented accessory identity separate from a complete-housing identity, even where their records refer to the same connector system. The practical distinction is between explaining the feature's role and identifying an actual supplied configuration. Neither question should be filled using the other one's terminology alone.
4. Describe the retention item without an assembly verdict
The term terminal position assurance describes a product feature; its presence in a description is not a report that offered contacts have been checked for seating. A seller can preserve the supported feature identity while leaving the assembly's actual state outside that classification. Likewise, a loose accessory may be identifiable without demonstrating that it has been installed. Keep those statements distinct so an enquiry for retention items does not accidentally become a claim about the correctness of a complete connector assembly.
For an ICULTRA enquiry, identify whether the released item is the accessory, a housing with a documented feature or a larger assembly. Explain the supported terminal-retention role and retain any separate component references. The general stock-list and container guides cover quantity units and grouping; they should not convert loose accessories into complete connector sets. This review supplies no mating, seating, cycle or vibration result. Ask the recipient to review the identified deliverable and confirm the assessment and commercial scope separately, without promising fit from a shared family reference.
Sources and further reading
Molex's bounded official contact-retention web text supports the retained-object, primary-lance and secondary-TPA distinctions. Implementation varies. No loose-supply rule, physical fit, installation or contact-seating result is supplied.