28-Position Single-Row Receptacle for Board-to-Board Stacking
Tin-Plated Contacts and Mating Cycle Life
In a production board that is assembled once and rarely reworked, tin plating is the practical call. For field-service connectors that see quarterly disconnect, gold would be the better bet, but this part is not plated for that duty.
Both dimensions matter when fitting the receptacle into a tight board stack or when the mating header has a specific shroud height.