These are incandescent bulbs, they work as advertised but I noticed a slight delay (<1s) between pressing the switch and the light turning on. For example, I have a ceiling light with three different bulbs, and while the other bulbs (of a different brand) light up instantly, you can actually notice the lag of those bulbs. It doesn't really matter much, I don't even realize it, but I probably won't buy this product again just because I get easily annoyed by small inconveniences.