Circuitron A 5501 BD-1 Optical Detector - With 4 Opto-Sensors March 21_24_DON B Thanks to its compact shape

Thanks to its compact shape and versatile uses

last but not least

Length over the buffers approximately 210 mm / 8-1/4"

its great for adding a FRED at the end of the train

Circuitron A 5501 BD-1 Optical Detector - With 4 Opto-Sensors March 21_24_DON B Thanks to its compact shapeTiny Opto Sensors detect train movement. Sensors mount between the rails and activate circuitry when shaded from a passing train. Independent of track power, rolling stock requires no modifications. Sensors fit between ties and may be ballasted over in most cases. Circuitry is extremely sensitive and will operate properly under very low levels of room light. Positive indication whenever a section of a layout is occupied by rolling stock. Contains all