Why does dB140 have two different sounds?Updated a year ago

The piercing duo-tone sound is designed to be heard through car windows and above the ambient noise. The secondary car-horn 'park mode' sound it more of a traditional ‘beep’ sound which is less audible on the road but works much better for pedestrians in a park or on a trail. You change the sound mode by pressing the “H” button at the rear of the main unit.