It's the whoosis next to the volume control. 就是在音量控制钮旁边的那个东西。
Thus, delivery pressure remains constant even as cylinder pressure decays, eliminating the need for frequent control knob adjustment. 因此，即使钢瓶压力下降，调整器的输出压力保持恒定，从而不需要经常调整控制钮。
All functions are controlled by a simple control button arrangement mounted on the front panel. 所有功能均可由前面板上的简洁的控制按钮来操作。
