Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Exactly what I wanted

If you want a quick way to see if the reason your device isn't working is because of dead batteries, this is exactly what you want to use. Very easy to do - pop each battery in and see if it's in the red. Also good for when you find a random battery in a drawer and want to know if it's any good. I also plan to use it periodically to see if I need to change out my fire alarm batteries. I'll probably toss them if they're in the yellow or worse (though for something like a TV remote I'd put them back in at the yellow level). Some people have an issue with this product because it won't "measure load" or doesn't "test under load." If you want to know exactly how much power your battery has, no, this won't work. But for the above reasons it's great.