This is an oddball inverter, about the size of a couple of old Reader's Digest magazines and limited to a single two-prong AC receptacle and 0.5A USB output, but it has some interesting features that might fit an off-grid niche for some use cases.
At a bit over $100 it's certainly not cheap, especially when compared to what's available in modified-sine wave units of similar power output, but it connects easily to DC sources with the standard ham radio powerpole configuration and works great with battery packs (like 12V Bioenno LiFePO4) that come wired that way. A high quality cord, with ferrite bead winding, that fits a standard cigarette lighter receptacle is included for those that aren't interested in rolling their own powerpole cords.
I used it the last two nights to run a CPAP machine off my 20Ah Bioeeno battery, which has a similar desktop footprint. Monitoring the battery load via a Watt's Up meter, I found that the inverter drew just under 0.25A by itself and ran cool and quiet under the less than 2A peak load of the CPAP machine. My CPAP's power consumption fluctuates dramatically with the cycle of respiration, going to nothing on inspiration and averaging under 1A (CPAP and inverter combined) overall, such that 18 hours of sleep over two nights consumed less than 14Ah. Online reviewers have mentioned that this unit puts out much less RF noise than other Samlex PSW inverters, at near-touching proximity, but I haven't tested that yet.


Here's the Samlex spec sheet:
http://www.samlexamerica.com/documents/product-specs/12001-PST-120-12-1116.pdf