Perhaps what I should have said is if you take another device, but a resistive load of an appropriate value across it, do the same for the D1, and keep the speed the same - you'll get more wattage from the D1. You can't make energy, only convert it. The D1 converts more and the figures in the chart posted above prove it.

I'm quite happy to compare with one of the devices mentioned earlier. I don't need the batteries (they lessen efficiency), just the circuit board will be enough to produce the figures.

If you're not after efficiency, perhaps the ultra small size, the titanium case, the epoxy IP69 inner, the resilience (components are 25yr rated, the outside capacitor has a 10x increase in working life over standard). The lifetime warranty. The rebuildable USB port...

The price is much less than a Supernova The Plug, a bit less than an eWerk and a bit more than USB Werk (at least in the UK). Read the website and if it still doesn't blow your skirt up... let me know why.