Accounts DES July 23, 2017 The different types of bulb fittings Accounts DES July 23, 2017 Ever wanted to know what type of fitting your bulbs have? Use this handy guide!E27 Also known as "Edison Screw", the E27 is commonly found in downlights. B22 The B22 is commonly called the "bayonet' fitting. MR16 The MR16 has two thin pins and is found in downlights. GU10 The GU10 has two thick knobs on the back, and goes into the light fitting by twisting it.