Double-reed mouthpieces are used for oboes and bassoons. They are similar to single-reed mouthpieces, but they have two pieces of reed that vibrate against each other. This creates a more complex sound than that of a single-reed mouthpiece.
Flute mouthpieces are not made of wood, but they are included here because they are also part of the woodwind family. They are made of metal or plastic and have a hole in the center that the player blows air through. The air stream impinges on the edge of the hole, creating sound.