These Spring Headers are imported from Japan and can be used to make swapping of microcontrollers quicker without the need to desolder the connections.
When used with Elite-C and Pro Micros, these headers will need to be soldered to the microcontroller. After that, the controllers with headers attached only need to be pushed into PCB footprint in order to make a good connection. The pin holes are small enough on nice!nano controllers, so soldering is not required when used with n!n controllers.
The headers make a good connection without soldering to all kits currently sold on the site.