I bought a 3 pack of the fly killer the instructions clearly say to lock the trigger and leave the house for 4 hours. I followed the instructions and when I came back later, 2 of the cans were still full and the trigger was in the lock position. I tried several times to get them to lock but they wouldn’t. Of the 3 cans only 1 worked. I felt really cheated and wasted my money. I would not recommend this product.