Description: Material: The RC model car sound group is made of abs shell, metal electronics ,which is sturdy for long term use Compatibility: Remote control car sound is for 1/28 1/24 1/18 1/35 climbing car truck Easy to Install:This rc car part is easy to install tp replace old or broken part. Control Method: Once turned on, the engine sound will automatically start when throttle channel moves for the first time; if idle for over twenty seconds, it will automatically shut off but restarts upon throttle movement again. Note: The maximum supply voltage for the sound group is limit to no more than 5V to prevent damage to the built in amplifier and unit (MCU). If your Electronic Speed Controller (ESC) BEC is rated at 6V, it's recommended that you connect two diodes rated for two amps in series from the for power reduction. Specification: Output power: 1W8 ohm 5V/0.6 W8 ohm 3V input: positive 0.8 ms to 2.0 ms Sound quality: 22.05 kHz sampling frequency Memory: 4M, 22.05 kHz audio about 20 seconds Size Chart: 8cmx12cmx1cm/3.15inchx4.72inchx0.39inch Package Includes: 1 RC Sound Group Note: Please allow slightly errors 1-2cm differences due to manual measurement.