I have 2 negatives for this brand. I have to buy a different brand for my study light as the Philips won’t fit the socket. And yes it is the correct fitting that takes a bayonet cap. Quite annoying. The other negative is that these globes don’t have the life expectancy as printed on the box. Apart from that I do like the Warm White as it is more natural than the cool white and when it does work in the sockets it fits into the light is nice and strong.