Is it illegal to change a truck into a snail horn?

It is not illegal to modify the snail horn of Geely Automobile, but the volume of the modified snail horn must be adjusted to a suitable position, and the volume should not be too large to affect other vehicles. When we use the horn at ordinary times, we must not use the horn casually in the area where whistling is forbidden, otherwise it is a road traffic violation: once it is found, it will be scored or fined.