My brother recommended this product to me as a convenient way of controlling multiple audio out devices. I currently have a speaker system that was plugged into the 3.5mm jack of the soundcard in my PC. I have an audio DAC that I have plugged into my PC via USB to use for headphones, and I have a USB microphone plugged into the PC as well. The inconvenience for me is that I have to constantly switch the Windows audio device from the DAC to the built-in soundcard to switch between my headphones and my speakers.With this set, I have the microphone plugged into the box via XLR, my headphones via 3.5mm jack into the "Headphone" output, and the speakers plugged into the "Line Out" output. I then connect the box via USB to a KVM switch which I use to switch between my main pc, my work docking station, and my home linux server. This allows me to use my headphones and/or my speakers on all 3 systems, along with my microphone. Extremely convenient for my setup and for my use case. There is an additional 3.5mm "Line In" input that you could also add another input to (e.g. PC USB, some other system via "Line In"), but I don't use this input currently since USB provides the sound for my 3 systems via KVM.It does have a 3.5mm port for a headset microphone in addition to the XLR port. I tested a Razer headset that has both the mic and headphone in one plug and it did pick up the mic and did play sound through the headphones. The volume is controlled by the "Headphone" slider as well. The Razer headphones have a volume control on them as well, and cranking it to max, I did not notice a difference in volume between the Sennheisers I have plugged into the "Headphone" jack vs the "Headset" jack. So you should get full volume and control to both ports simultaneously if needed. It does appear to disable the XLR microphone, though, if you do have a microphone plugged into the "Headset" port. So if you purchase just the audio mixer with no microphone, it could work for you to control a headset and speakers.For this combo, connecting the microphone to the box via XLR does not provide any control or capability to drive the LEDs on the microphone, so don't count on having that. I have not tried the microphone via USB since this doesn't really matter to me and isn't ideal for my setup.I am very pleased with this purchase. At the time I purchased this, I got the combo for under $100. Unbelievable value for the convenience provided for my setup, I absolutely love it.