Instruct: Classify the given Amazon review into positive or negative sentiment.
Query: Works well, but zipper breaks easily

I bought two of these when they were on sale on Amazon and I have to say I was happy for awhile. Unfortunately, the case hasn't been tested well, because the zipper is DEFINITELY not strong enough.It broke once and I had to exchange it for a new one. Then the new one broke also. This doesn't happen if you don't have many discs... say 100. But once you get to the 150 mark, you can feel the strain on the zipper everytime you open or close it, and what's the point of buying a 320 case if you only fill it to 150?The case holds the DVD well enough, as long as you don't need to close it.