While these Grocery Bag Brass Knuckles may have a non-violent practical use, it doesn't mean that they won't be helpful should you find yourself in a scuffle.
These Grocery Bag Brass Knuckles are designed not to hurt people, but to hold up plastic bags. If you look at the side of these items, you'll see that there are two hooks that are specifically designed to hold onto the handles of grocery bags. Considering how much strain plastic or nylon bags can put on your fingers, I can see how useful this jaw-breaking item can be to shoppers.
Next time you go shopping, have the Grocery Bag Brass Knuckles on-hand. When a sale goes on and people are running with rampage, you can always protect yourself with this bad boy.