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Orlandoo Hunter Model Diesel Sound Unit Kit - SC0001
Small footprint, easy to install diesel sound system that can be used for micro sized crawler to 1/10 - 1/32 scale crawlers. Its got realistic sounds for engine start, idle, throttle, full throttle and reverse.
The volume is not adjustable. To generate a louder volume, you can DIY a amplifier system with cardboard cutouts to amplify the sound. The volume is loud enough for trailing, is not loud enough to disturb your neighbours or annoy them.