I heard from a not-too-reliable source that there's a new law in California that will require all bicycles to be equipped with a horn. Whether or not this is true, someone really needs to make a good horn for a bike. I know of no such device on the market. If someone does, please educate me. What I call a "good" horn, would:

Be electronic
Adjustable loudness from "soft" to "pretty damn loud"
Be light weight
Come with mountings that would accommodate various situations, such as on fat carbon handlebars and mounting on the head tube. In fact, any accessory made for mounting on handlebars should have this!

Stupid law.