Review on 🐠 Conveniently Programmable NICREW Aquarium Light Timer & Dimmer - Enhance your Fish Tank Lighting Control by Cynthia Taylor

It doesn't work like clockwork. The timer only has three presets that you can choose how long it stays on: 8, 10 or 12 hours, that's it! You can't set it to turn on or off at specific times. For example, if you want the light to turn on at 10:00 AM, you need to set the "on" time period and press the power button at exactly 10:00 AM. It will then stay on for 8, 10 or 12 hours depending on what you choose. These are the only options. If you accidentally turn it off, for example during weekly aquarium maintenance, you will need to reset the timer again. Personally, it annoys me a lot. Update: I've only had it for a few weeks and the 'timer' feature has stopped working. Now it's just a built-in switch. Very dissatisfied!