Zoo Med AquaSun Aquarium Timer

The timer does its job, however it does not come with detailed instructions. You have to push down a series of pins around the dial to indicate which hours you want it to be on, set the dial to your current time, and then plug it in. It seems like if you don't plug it in at the exact time the dial is set, it will not turn on and off at the exact time you want it to (I set the dial for 4:00 pm and the "on hours" from 7am-7pm but didn't plug it in until a few minutes after 4pm and as a result my aquarium light didn't turn off until a few minutes after 7pm). It also only seems to work if you set it up during the time you want it to be on. For example, I tried to set it up after 7pm at one point and could not get it to work, which I think is due to a small switch inside the dial not being activated from the pins that are pushed in for the "on hours". The "on hours" not being accurate to exact times is not a big deal but a notice that the timer won't work unless you set it up during the "on hours" would have been nice. The product is very analog and not very intuitive but it works as advertised and would have been 5 stars if not for the vague instructions. Hopefully this helps someone and I do still recommend the timer.