Arklove 1/8" aux Input Mixing 2 in 4 Channel Way Out Headset Box Headphone Amplifier 3.5mm Mixer 1/8 inch Stereo Audio Amp with Ultra-Compact Portable Mini Jack 3.5 Splitter hup for Studio and Stage

This allows for perfect volume control for all seating areas on the boat, and gives me the option to have multiple inputs too.

I have two computers that I needed to be able to hear both sound inputs and this fixed my issues. It has knobs to turn the individual sound sources up or down and knobs for volume control for the outputs as well. Very very happy with this purchase. Did everything I needed without fuss.

I was looking for something that would allow me to mix audio input from my digital piano and ipad and be able to listen via two separate sets of headphones. I've used other small mixers like this that unfortunately had very poor audio output with overdriving distortion or very low volume. This item provides great sound output at low to medium levels for two sets of headphones without the need for an audio splitter. Great sound.

Heavy Duty and it works nicely to replace my 1-3 aux cables

Update: it seems like the issue may have been coming from a ground loop, which wouldn't be the fault of this mixer. Updating to 4 stars so as not not unfairly impact ratings, as I can't know if this device contributed and to what degree.I was looking for an audio mixer with 2 inputs and 2 output (all 3.5 mm) and this seemed to be pretty much the only basic option on Amazon. Unfortunately, the level of noise added by the power supply makes it unusable, the speakers are constantly hissing with some pops. Maybe a nice clean power source could make it acceptable, but that doesn't change the underlying problem with the isolation in the switch.