Boss AB-2

used this switcher to switch between bass and synth and it does so without any extra noise
+sturdy build
+battary powered
+ clear indicator leds
- plastic switch

As said, it is perfect, well built, totally silent (in a room where you do not want noisy switches, here is a winner), it does the job with no issues at all. Two in into one output, or one in into two outputs, with no flaws. Please, remember to disconnect the jack that switches the unit on, so that you do not drain uselessly the batteries, they will last for a long time (100 hrs) if you switch it off.

Great switch who uses more than one guitar on gig. Really best thing that every guitarist must have. It is also build like a tank, so you don't want to be worried about quallity.

Well build, easy to operate, great price. if you need an AB selector pedal, this is a top choice.

Much more solid that you'd think and they work great. Don't leave them plugged in though or it will drain the battery.
I used two together to switch between 3 basses. never let me down.