A receptacle carrier is a convenient way to pick-up and place individual sockets (receptacles) as a group. It is essentially an assembly fixture having an array of protruding pins, onto which are pushed individual receptacles.
The receptacles are held in place by their internal spring contacts. The carrier assembly is placed into a corresponding group of holes on the circuit board, and the carrier holds the receptacles in position during the wave or reflow soldering cycle. The carrier is then removed after soldering, leaving behind a group of receptacles to be used as a socket for a leaded component.
See below for further information:
https://www.mill-max.com/engineering-notebooks/introduction-to-pin-receptacle-carriers
