I have 3 nicrew lights that are all about 4 or 5 years old, they are still working well. The power to the lights is low voltage DC so I don't worry too much about them being waterproof. I have dropped a couple of them in the water and even though they were in the water they still lit. Took them out and dried them, still working, though I expect they are slowly corroding. If you have a saltwater tank I believe they would die soon after being dropped in the water. Mine are definitely not waterproof, and I expect if you used them long term over open water they might degrade due to corrosion. I keep mine over the glass covers to the tank.
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