The Bestagon Micro Filament Runout Switch is a small 3d printer filanent runout switch designed to be placed in line in your PTFE Tubing. Using a ball bearing and an Omron D2F Micro switch, this little guy works great for all your filament runout detection needs! Its so small and light it doesn't need to be mounted however if you want to mount it there are 2 M3 brass inserts for you to do just that. It comes in two variants, one with just the switch, and one wired to a 2.54mm JST-XH plug.