There are various horn shapes and styles that are used in ultrasonic welding depending on the specific application requirements. Here are some common types of horn shapes and styles:

1. Flat horn: A flat horn is the simplest form of horn used in ultrasonic welding. It has a flat surface at the welding end that is used to apply pressure to the workpiece.
2. Tapered horn: A tapered horn has a gradually decreasing cross-sectional area from the base to the tip. This shape helps in increasing the amplitude of the ultrasonic waves at the tip of the horn, resulting in better energy transfer to the workpiece.
3. Stepped horn: A stepped horn has a series of stepped sections that decrease in diameter from the base to the tip. This design helps in minimizing the energy loss due to resonance and reflection.
4. Hourglass horn: An hourglass horn has a narrow waist in the middle that helps in focusing the ultrasonic energy at the point where the workpiece is welded.
5. Horseshoe horn: A horseshoe horn has a U-shaped profile that is useful in welding parts with a large surface area. It provides better access to the workpiece and reduces the need for multiple welds.
6. Cylindrical horn: A cylindrical horn has a uniform cross-sectional area along its length. This shape is useful in welding cylindrical parts or when a uniform weld is required.
7. Blade horn: A blade horn has a thin profile and is useful in welding parts that require a narrow weld zone.

These are just some examples of the types of horn shapes and styles used in ultrasonic welding. The choice of horn shape and style depends on various factors such as the material being welded, the geometry of the workpiece, the required welding strength, and the desired welding speed.