This is a trumpet, a brass musical instrument that produces sound when the player buzzes their lips into a mouthpiece.
Here is a breakdown of how it works and its main parts:
How Sound is Made: Buzzing your lips creates air vibrations that travel through the brass tubing and project out through the flared bell.
Valves (The 3 Buttons): Pressing different combinations of the three piston valves changes the path the air travels, altering the length of the tubing to lower or raise the pitch.
Tuning Slides: The adjustable loops of tubing allow minor adjustments to fine-tune the instrument's pitch.
Water Key (Spit Valve): The small lever near the bottom release valve lets out accumulated condensation from playing.