These are the profesional sets of bug spy transmitters and frequency-matching receivers. All the sets are working on the UHF band, and they feature the most prominent quality.
The distance you can achieve differs in urban areas and line of sight areas, without obstacles. Matching transmitter and receiver on these sets is unique and incredible.
Room surveillance requires a small but powerful audio transmitter and a sensitive receiver. Their small size made them the best kits in the market.