After having a couple of electric bikes stolen, I decided to invest in a bike alarm. This was perfect for my application. It works great. The horn is very loud - I actually wish I could lower the sound, but it does the job. The alarm has variable sensitivity, and the keychain remote control is very well built. overall a high quality product that I would recommend.
The car people in my neighborhood aren't known for paying attention basically at all. And the stock horn on my scooter doesn't sound like a horn, so nobody knows what it means. But this horn, on the other hand? It sounds like an actual car horn. It means business. It means pay attention to the crossing lights. It means stay in your lane and share the road. It means drive safe so I can ride safe. And it has a super sensitive vibration alarm function, so it also means don't touch my bike.
This high quality metal horn as used on motorcycles and scooters for road use. This is effectively loud. Anyone attempts to steal your e-bike it senses tampering and sounds the alarm which will send them running.