Good piece of kit for the price, acceptable for studio. Build quality is good, fits the rack fine. 4 channels with 3 headphone outs. Flexible in use through routing signal as needed. Main Input (on the back) will be heard across all channels and aux inputs (on the front) will be heard across each individual channel. So you can have 12 headphones from one mix, or 4 stereo submixes depending on your output source (desk/audio interface with suitable amount of aux outs/outs etc) or Main mix with "more me" per channel if using a mono output source (ie, bass/guitar/vocal). Has function to sum each channel to mono in case the aux is used with a mono source (eg send 3 of send/return on your 8 channel preamp etc), and can mix between Main and Aux input sources (in mono). I've found it very useful with Totalmix (for any RME users out there) or anything else with flexible routing.