This filament sensor allows you to automatically pause your 3D printer if the filament runs out or gets stuck. You can install the sensor purely as a “switch”, or you can also monitor the material supply. This allows your printer to detect tangles or a clogged nozzle and pause it. For 1.75mm filament. Adjustments to the printer firmware are necessary. Compatible with Marlin 2, Klipper and RepRap firmware.