Works great

It accurately measured something with it. Only difficulties are that you NEED headphones, even on the iPhone, and it is extremely hard to figure out. Tip for people who cant figure it out. It measures from microphone to speaker. In single device mode it measures from your left headphone to your headphone or iDevice mic. In dual mode it measures between devices. Note that it MUST be calibrated or else it will not work. Calibration sets the 0.0 point which needs to be set properly. Also you have to align it properly (shouldnt be a problem).

EG73086298 about Acoustic Ruler Pro, v2.0