There is nothing in the spec and the pictures to give you a clue that this is NOT going to fit a standard breadboard. On the other hand, there are clues that it should - this site pops this product alongside Arduino / other hobby plug-n-play - all of which use 0.1" through-hole spacing. The pins on the picture even look a standard DIP package pins.
Well, the actual spacing appears to be 2.0 mm.
An extra PCB and some soldering and it's doing what it was supposed, but I wasn't planning on it.
Other than that, it appears to be a quality product in every way. Due to a wiring mistake, I have unexpectedly tested the matching between the two pots: pretty close to +/-3% across the sweep. At least for that unit.
BTW: The sweep is linear, not logarithmic, as might be preferable for something that is obviously aimed at stereo audio volume control.