When sourcing horn valves, the material composition is paramount; look for high-grade brass or stainless steel to ensure corrosion resistance. Pay close attention to the bore size and taper, as these directly impact airflow and acoustic response. For musical applications, ensure the rotary or piston mechanism has a tolerance of less than 0.01mm to prevent air leakage. For industrial horn valves, verify the maximum pressure rating (PSI/Bar) and thread compatibility (NPT/G) to ensure system integration.