Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Industrial material!

This is one tough finger toothbrush, it's very hard rubber? plastic? and will not flex when it is on your finger. The brush "nubbins" work well, but it's uncomfortable for me to use in my 20 pound dog's mouth. It's bigger than my finger, and slides around while it's on.I would not recommend this particular product.