The interior of the fitting is made of porcelain.
|Height of fitting (cm):||5.8 (2.3 inch)|
|Outer Diameter (cm):||4.5 (1.8 inch)|
|Fitting:||Large size socket E27|
Fitting, white porcelain, large socket (E27).
At the top is internal thread 1.0 cm (M10) 0.39 inch.
You can use this, for example, to screw in your strain relief or the end of a tube/rod.