It appears the DT-500W is powered by a rechargeable Li-ion Polymer 3.7V (1850mAh) battery. I would expect good longevity from a full charge.
Based on the specifications, the receiver covers all NOAA weather radio frequencies, the FM broadcast band (87.5 – 108 MHz) and the full AM broadcast band (520 – 1710 kHz). I also noted on the spec sheet, however, that the AM broadcast (mediumwave) band is limited to 10 kHz tuning steps. Not a great contender for the ultralight DXer or someone who travels outside North America if so!
As of posting, I can’t find the DT-500W listed with any online retailers.
Thanks again for the tip, Jeff!