Instruct: Classify an Amazon review into positive or negative sentiment.
Query: A good little sharpening stone.

I bought two of these, one for my urban manbag and one for my bugout kit. They work very well for their size; they retain oil easily, so I don't have to worry about them going dry, and it's very easy to get a fine edge on whatever I happen to be sharpening. I'll definitely buy more of these if I ever wear out the ones I have now.