Features Whisper wireless tour guide system,lightweught and small size,convenient to take. Widely applied to teaching,training,museum,outdoor scenic spots,exhibition/conference center,simultaneous interpretation... Use mini Jack MIC cable,can input CD,MP3...external audio source. One Transmitter can cover hundreds of pcs Receivers,stronger,anti-interference ability,sound clearly,more stable performace. 99 channels,815MHZ-823MHZ,99 IDs allow 99 groups to use simultaneously. Description Product Description Color: 1 Transmitter and 80 Receivers Fetures: 1.Whisper wireless tour guide system,lightweught and small size,convenient to take. 2.Widely applied to teaching,training,museum,outdoor scenic spots,exhibition/conference center,simultaneous interpretation... 3.Use mini Jack MIC cable,can input CD,MP3...external audio source. 4.One Transmitter can cover hundreds of pcs Receivers,stronger,anti-interference ability,sound clearly,more stable performace. 5.99 channels,815MHZ-823MHZ,99 IDs allow 99 groups to use simultaneously. 6.UHF for international free frequency license. This system is designed especially for guides and group.It is a lightweight,multi-channel sysytem that helps tour participants listen directly to the tour guide clearly.working distance up to 200 meters.It Can hang in the chest,can also bi in the waist,more conveniently. Specification: Transmitter & Receiver: Frequency Range:815MHZ-823MHZ Frequency Stability:¡À2ppm Modulation Deviation:7.2khz Second harmonics:¡Ý40?dbc Receiver sensitivity:-105dbm Transmitter current:<110mA Receiver current:70mA Locked Technology:PLL Digital Lock Working Temperture:-20¡ãC~+70¡ãC Out cover Material:ABS Battery type:Built-in Lithium battery Battery life:15 hours Talk range:200 meters Application: Museum,school,training,horse rider training,outside travel group,indoor tour team,Hajj,church,meetings,etc. Package Contents: 1 x Transmitter 80 x Receiver 1 x clip-on microphone 80 x Single hook earphone 81 x charge 81 x lanyard