Hard to say there are so many rip-off's of this nature. This one is especially vague as to "how" it claims to increase power. Most of these you plug into the ECT to make the PCM think the engine is colder. This causes cold enrichment that with WOT (wide open throttle) and up to a limit of enrichment, will produce more power. Again _only_ with WOT. So the "claim" is true but grossly misleading in what you can expect in results from behind the wheel.
This device appears to specifically disclaim this type of "power" improvement. Another way to do the same thing with most any Honda fuel system is to skew other primary input load signal (TPS, MAP, etc.) similarly to achieve enrichment at wide throttle openings and therefore achieve a similar result as the ECT "trick".
I can't imagine someone selling such a device doesn't know the correct spelling for the Honda Insight. Sounds like he's trying to keep a low profile, not a good sign.