BA22d
BA22d is a type of bayonet light bulb cap. It is a standardized fitting used for certain types of electrical lamps, particularly in the United Kingdom and some other Commonwealth countries. The designation "BA22d" refers to the dimensions and configuration of the cap. The "BA" indicates a bayonet fitting, and "22d" specifies the diameter of the cap in millimeters and the number of locating pins or slots. Specifically, it has a 22mm diameter and two locating pins. This design ensures the bulb is securely held in place and makes electrical contact when screwed into a compatible lampholder. BA22d caps are commonly found on incandescent, halogen, and some LED bulbs. The bayonet fitting is known for its ease of use, allowing for quick replacement of light bulbs without the need for tools.