Given reviews from Amazon, classify those review based on their content into two classes: Negative or Positive.
Q: Pro: Soft-closing valve mechanism prevents water hammer effect.Cons: Programming is not intuitive. Cannot adjust the manual valve-open time duration; it is fixed at 15 minutes (the manual states it is possible to adjust this, but I did not see how). 9V battery didn't last a week.
A:
Negative