I missed having a filament runout sensor so bought this to add to the V2.4. Out of the box it does not work very well, need to take it apart and gently bend the microswitch arm until it actuates reliably when filament is pushed thru.
Also need to be careful over time with filament debris collecting inside the unit (happens if you swap filaments all the time like me) which can jam the switch and cause it not to function. Good thing the body is clear so you can see it all!
Configuring the sensor for klipper was a bit of a pain. My first attempt worked, but sometimes weird things would happen when I would yank the filament out of the sensor while doing a color change and end up ruining the print. I ended up adding a setting to disable the sensor after it triggers to prevent this.