The number of beams indicates the quantity of infrared rays connecting the transmitter to the receiver. More beams mean greater coverage height and fewer false alarms, as all beams must be interrupted simultaneously to trigger the system.

The range indicates the maximum distance (in meters) that the transmitter can be from the receiver in order to operate reliably.

Usually, the greater the length, the more beams there are in the device, and therefore the greater the coverage length of the detector.