Here are some videos from Aaron Tunell, the original creator of the Tunell monitor. We have a collaboration with Aaron and are now selling an upgraded version (Version 4) now.

Filament running out: https://www.youtube.com/watch?v=JWRNVMoyRus
Filament getting stuck: https://www.youtube.com/watch?v=ItIOlt-Mq-k
Dual-monitoring: https://www.youtube.com/watch?v=Kw9-eVxrqn8