Vacuum No Sound Transmission Introduction: Next to the "Vacuum No Sound Transmission" device, visitors can press the button and observe the change of the electric bell in the vacuum cover after the air pump has exhausted the air in the vacuum. .
Vacuum No Sound Transmission Introduction: Next to the "Vacuum No Sound Transmission" device, visitors can press the button and observe the change of the electric bell in the vacuum cover after the air pump has exhausted the air in the vacuum. .