E27 Solderable screw base. The ground or neutral wire is soldered to the inside of the threads. The line voltage wire is soldered to the tip on the bottom. There is no plug or pin at the bottom, since it is a solderable E26. The inside diameter is 25.35mm. The outside diameter at the tip is 26.14mm. The outside diameter on the open end is 27.02mm. The length is 26.80mm. The E27 base is made of copper plated nickel. The heat resistant temperature is 300°C. The rated voltage is up to 277 VAC. The rated power is up to 1100 Watts. The rated current is up to 4A. The weight is 7g. Great for hobbies, such as making your own lights! CE and Rohs.