Reminder to myself what these little circuit boards are for, after finding a few of them and having to investigate online. Also means I don't have to go out for a wander in the cold, dark, and rain falling on frozen ground.

Top one is a 2.4GHz wireless transceiver, and the lower one is an adapter that allows it to be used with the likes of an Arduino Uno, and other programmable devices.

Fear not if you're none the wiser.