You can set 5 styles sound mode for your RC car to create a realistic racing environment. and it can install in most of the RC cars as it has a small size to fit in. Features Advances SGS (Sound Particle Synthesis Technology) and SFC (intelligent State-following compensation technology) are adopted. 10 engine sound and 5 alarms are supported. Support brake sound and exhaust valve sound;And brake sound can be set to ON/Off freely. Standby mode supported it standby with no radio operation in 60 seconds. Move the throttle to wake it up. Low-voltage protection is supported, and battery types(2S-4S Lipo) are automatically detected when powered up. Specification: Item name: Model Sound Simulator Input Voltage: 6.5-16.8 V (2S-4S Lipo) Speaker Power: 5W Speaker impedance: 4 Mono model size: 46 x 46 x 42 mm Dualmodel size: 81 x 52 x 42mm Package size: Mono mode 73 x 71 x 58 mm Dual model 105 x 75 x 56 mm Mono model weight: 113 g Dual model weight: 169 g Note: There could be a few deviations due to manual measurement or slightly color difference as the result of the shooting scene. Thank you for your understanding. Package Listing: 1 * RC Car Engine Sound Simulator 3 *Adapter Cables 1 * User Manual