Taoist, what is a trumpet instrument?

The horn instrument is a Taoist priest of Aconitum. Aconitum monks use horns, and red-headed monks use tin horns. The horn symbolizes the cauldron in the inner alchemy of Taoism later. Like a crescent moon. Two corners are opposite, and half a circle is on Kun. The round bottom is like copper ground and the solid wall is like gold. It is five inches wide and there is no obstacle in the middle.