... ,Holding Cells,Booking Rooms,Cell Monitoring etc.. S.Tradio audio surveillance kit for law enforcement, such as:Police Interview Rooms,Holding Cells ... , headphone, soundcard of PC and anywhere CCTV installed, the maximum wire transmit distance can reach 3 Km(shield cable is required ... 's Material PVCSize 103mm × 50mmWeight 50gStandard CE S.TRADIO audio surveillance kit specialized in Law enforcement