Instruct: Classify Amazon reviews into positive or negative sentiment
Query: I've tested it..

Went to a junkyard with my brother and tested this tool out. It definitely works. We cut through the seatbelts in a handful of older model vehicles and broke the windshield on one and the side windows on another. You defintely need to put some umph behind your jab, but I don't see that being a problem when you're going on adrenalin in a life/death situation. I bought one for all of my brothers and my parents who travel a lot via RV.