The first is the infinitely variable gain control on the rear of the mic, which delivers a wide output range (numbered 1–15). You can use this to precisely tailor the output level to best match for your device.
The next button is the power/function control. By default, the mic will auto-power on when connected to a device and power off when disconnected from a device, but you can also turn the mic on/off manually by holding this button for three seconds. A single press on this button will engage the -20dB pad (left LED illuminates), another press will engage the safety channel (left LED off, middle LED illuminates), and third press will engage both functions (left and middle LEDs illuminate). A final press will disengage both functions. The right LED is the dB peak warning light, which will illuminate red when the mic’s internal preamp is clipping, at which point the pad should be engaged.
The final button is the filter control. Pressing this once will engage the 75Hz high-pass filter (left Led illuminates). Pressing it again will select the 150Hz filter (middle LED illuminates). A third press will disengage the high-pass filters (left and middle LEDs off). A long press (3 seconds) will engage the high frequency boost (right LED illuminates). This can be used in conjunction with the high-pass filters. Another long press will disengage the high boost.
There is also battery power status indicator. Green indicates the battery is fully charged, amber indicates medium charge, red indicates low charge, and blinking red indicates very low charge.
This LED also indicates charging status when the mic is connected to a power source. When connected to a computer, green indicates it is fully charged; blue indicates it is charging. When connected to a power bank or USB power adapter, the LED maintains the red/amber/green behaviour above. If the power LED triple blinks red, this means that mic has detected it is outside its operating temperature range.