Features: FM frequency range 60-108MHz(0.1MHz spacing between channels) One transmitter can work with multiple receivers within the operating range Individual volume control on each receiver Both transmitter and receiver use LCD-display to indicate frequency,channel,battery,level status Specifications Transmitter: Model: EX831TransmitterBlack Frequency range: 60-108MHz (adjustable) Frequency increase: 0.1MHz Frequency stability: 10PPM Frequency response: 50Hz-1500Hz Signal to noise radio: <60dB Transmission power: 0.01/10/100/200mW Reference distance: 50/60/70/80M Working hours: 8/6/5/3h Power: BL-5C 3.7V 1000mAh Charging time: about 5 hours Support TF Card: only support MP3 format Size: 80x58x18mm/3.1x2.3x0.7in Receiver: Model: EX102ReceiverGray Frequency Range: 60-108MHz Sensitivity: <3.5uV Signal to noise ratio: 45db Stereo separation: 32dB Power supply: 2 x AAA batteries(not included) Earphone jack: 3.5mm Tuning increase: 0.1MHz Built-in speaker: No Material: ABS Plastic Size: 92x53x13mm/3.6x2.1x0.5in Suitbale For Guided Tours Factories, Museums, Tourist Attractions, Zoos & Theme Parks, Cruise Ships & Buses, Schools, Meetings & Lectures, Employee & Dealers Training, Hotels and Resorts, Special Events.Educational Institutions, Corporate Meetings, Training and Seminars, Theaters, Governmental Agencies, Houses of Worship, Conventions and Auditoriums. Package Contents 1x EX831 FM Transmitter Black(Battery Included) 1x EX102 FM radio Receiver Gray(Battery NOT Included) 1x Antenna 1x USB charging cable 1x Microphone 1x Belt clip 1x Audio Cable (1.2 meter) 1x BL-5C lithium battery 1x In-ear Stereo Earphone 1x Lanyard 1x English User Manual