Solderless flashing of RTL8720dn castellated module

I am planning on using the rtl8720 module by itself in final production, rather than the bw16 breakout board.

In order to flash the module I need temporary connection that doesn’t involve soldering. This guy made a 3d-print you can use as a breadboard adapter for the module here. If you click on the link in the video description it brings you to the 3d-print download page, where he states that you need 21mm pin headers (which you can see him use in the youtube video). I cannot find these pin headers online. They pins are equally long on each side and are apparently 21mm long. Has anyone done this before and know where I can find these pin headers?

For the YouTuber, try pm for more info.

You can refer to [Ameba] RTL8720DN /BW16 二合一擴展板 Shield ~ 宅老大數位
Or in your case only use module, you can discus with Kevin for some PCB design suggestions.