Radar detectors in private vehicles are legal in Illinois. That said, radar detectors are illegal in commercial vehicles under the Illinois Traffic Code (625 ILCS 5/12-714).
A radar/laser jamming device is illegal in Illinois (625 ILCS 5/12-613). I am not familiar with the type of device you describe. If it is a detector only you should be fine. If it is a jamming device, it is illegal.
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In Illinois, radar detectors are only illegal in commercial vehicles under 625 ILCS 5/12-714. If you are operating a personal vehicle, you would not be subject to this statute. However, you must make sure that the model you specified is not a radar or laser jamming device. These devices are illegal in Illinois for all types of motor vehicles.