Disclosed are multibinding compounds which are \u03b22 adrenergic receptor agonists and are useful in the treatment and prevention of respiratory diseases such as asthma, bronchitis. The over-voltage protection circuit monitors a voltage across the high-voltage transistor to detect an over-voltage condition of the high-voltage transistor, and turns the high-voltage transistor ON when the over-voltage condition is detected. Additionally, the root element includes a directional property that is inherited by the child elements. The heater pipe has a passage between the first and second holes so that gas can enter through the second hole and exit through the first hole. The fourth merchandiser module is positioned next to the first merchandiser module and the second merchandiser module opposite the third merchandiser module.