gostcai Mini FM Transmitter Portable Wireless 70MHz ~ 108MHz Audio Stereo FM Converter Adapter Suitable for Home Car Classrooms Auditoriums Dormitories Squares

Features: Full-band work, the frequency from 70MHz ~ 108MHz range can be arbitrarily set. Excellent heat dissipation, stable and reliable power. Easy to use and operate. You can operate all functions on the interface. The FM Transmitter is unique with its small size, allowing Maximum portability-perfect for traveling. High signal intensity and good sound quality, suitable for home, car, classrooms, auditoriums, dormitories, squares, etc. Specification: Package Weight: 87g Transmitting Frequency: 70MHz-108MHz (adjustable) Boot Frequency is: 87MHz (Default) Stereo Resolution: ? 40db Signal to Noise Ratio: ? 65db Transmitting Power: ? 10mw Working Current: ? 75mA Operating Voltage: 2.2V-3.3V Standby Current: ?1uA Operating Temperature: 0-70 ? Transmitting Distance: 50 meters or so / 164ft Battery: 2 * AAA battery (not included) Instructions: 1. Connect the audio signal line, install the battery ( two AAA batteries), long press the "power switch"  to boot for 3 seconds. Then the display shows the 87MHz transmit frequency. 2. Select an appropriate frequency by the "Frequency +" and "Frequency -" keys, the  frequency word flashing. Then press the "OK" button within 20 seconds,  the frequency word is no longer flashing, at this moment, the frequency on the screen is Actual transmission frequency. 3. "Frequency Lock" key is used to lock the frequency: long press the "Frequency Lock" key for 3 seconds. When displaying "LOC" words, it means lock frequency work successful, the "Frequency +" & "Frequency -" key not working. Then long press the  "Frequency Lock" key for 3 seconds to cancel the lock function. Package Included: 1 x FM transmitter 1 x Audio Cable 1 x User Manual