 The E11 base is sometimes used for 50/75/100-watt halogen lights in North America, where it is called the "mini-can", and tighter threads are used to keep them out of E12-base nightlights and other places where they could start a fire.There are also adapters between screw sizes, and for adapting to or from bayonet caps.A socket extender makes the bulb stick out further, such as to accommodate a compact fluorescent lamp that doesn't fit in a recessed lighting fixture.