Bought it to use it not as mixer but 1 to 4 signal splitter. Works flawlessly, even when used in this "alternative" way. Just turn all the level knobs fully right and connect it backwards.
If used as mixer, you should to take into account, that as it is passive device and has approximately -12dB attenuation so you have to add gain afterwards to compensate signal loss. On the other hand, as it is fully passive, it does not add any of its own "colorization" to sound passing trough so in this perspective it is almost fully "transparent".
Solidly built with full metal body to last forever and it is really tiny.
I searched high and low for a phono RCA mixer and this was the only one I could find. I have used this lots of times and being passive (needs no power) it can be plugged in anywhere without having to have 'another' power adapter etc. I highly recommend this !!