Help identifying hollow spring / inverted header sockets

Question

I'm trying to identify the following hollow sockets which are used to interface with a 0.1" pitched header:

(source: US Digital PC5 Broadcom/Avago Compatible Incremental Encoder Cable Driver. https://www.usdigital.com/products/accessories/interfaces/cable-drivers/pc5/?q=PC5-H10)

Instead of normal PCB headers, these allow the PCB's themselves to be placed much closer together:

For the application I'm working on I need to interface with a 0.1" pin header (which can't be changed), and for various reasons I don't have enough space to use a regular socket header. So I'm looking for something similar to these sockets where the 2 PCB's can be placed closer together.

Can anyone help identifying these types of PCB sockets?

Answer 1

Digikey sells them: https://www.digikey.com/short/wnjj5m37

Their Digikey catalog section for this is:
Connectors, Interconnects -> Terminals -> PC Pin Receptacles, Socket Connectors

Mill-Max is one well-known manufacturer of them, they call them "Pin Receptacles".