I had a problem with the old 6 inch lights in my ceiling not lighting very well. Add to that the overlay rings that didn't really cover the loose holes in the drywall and the fact that I couldn't find ANYTHING in the big stores to seal the holes effectively. It's the perfect remedy for the situation. diameter 8 inches. The supplied template more than covers the existing holes. Careful cutting results in most DIYers being able to make a beautiful, professional-looking installation. And these things are bright and dimmable. After buying a set of 6 last month, I bought a second one to light up other spots in my house.