Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Check them as soon as you get them

Check them before you install them. I bought 5 of these for my sprinkler project. 3 had cracked solenoids (at the base of the solenoid on the threads) and one had a bad valve. I don't know if I just got a bad lot but 1 out of 5 is ridiculous.