The metered PDU LCD display shows the current power draw in amps. The metered PDU only has one function button, MUTE, located next to the display. The metered PDU's alarm sounds when the current draw reaches 90% of capacity (13.5 amps). The alarm can be turned off by pressing the MUTE button. When the current draw exceeds 90% the maximum current rating, the alarm cannot be muted, and the PDU alarms until the current draw is reduced.