This is a brass bugle, a simple signaling brass instrument.
It is made from brass, which ensures durability and a rich sound quality.
It typically has no valves or other pitch-altering devices, limiting it to its natural harmonic notes.
Pitch control is done entirely by varying the player's embouchure (lip tension).
Bugles have been used as military signaling instruments since the 18th century, for calls like reveille.
They are popular for military re-enactments, parades, or as decorative pieces.