Instruct: Classify Amazon reviews into positive or negative sentiment
Query: zircon i520 Stud Finder

I started with the cheapest Zircon Studfinder,(the 20 dollar one). That one worked for a few months and quit working. So i bought the next one up. The pro one for about 30 dollars. This one worked for a few months and quit. Thinking it was me, i bought the most expensive one, the i 520. That one worked for about six months and quit. I am a contractor and know what I'm doing with this thing. They are pieces of junk. don't waste your money on one of these things.