What is what key is trombone in?

The trombone is a brass instrument that is pitched in the key of C, which means that when no valves are pressed or slides are extended, it plays the C major scale. The trombone is a versatile instrument that is commonly found in classical music, jazz, and many other genres. It has a unique slide mechanism that allows the player to change the pitch of the instrument by moving the slide in and out. The trombone is typically played in orchestras, jazz bands, and marching bands, and is known for its rich and powerful sound.