Screw-mounted fittings are often used in bathrooms and toilet areas. Nowadays, these fittings are less used, but they are still available to provide the many buildings where these fittings are still hanging with replacement parts. The advantage of such a screw-on rim fitting is that you can screw in any type of lamp. You must of course adhere to the lamp power when it comes to a light bulb, but you can easily replace it with a CFL or LED lamp.