I'm not sure on the range, didn't even think to look. It is an instant read with REALLY BIG NUMBERS and a back light. I can actually read it in the middle of the night without straining to focus. As near as I can tell the accuracy is within a degree or two of true and the min/max temps don't turn off; at least not automatically. It has 3 buttons: min/max, clear (to reset the min/max), & light. A slider is used to switch between "in" or "out" temps.
I'll look when I get home to see if there is a namebrand on it. Where did I find it at Walmart; I have no idea. As luck would have it, the cats think they need food (yet again) so I'll be at Walmart tonight. I'll see if I can find it again.