This is a metal spring washer with an inner diameter of 1.3 cm / 0.51 inch (M13). We ourselves use this spring washer between the fitting and the lampshade. In this case, the spring washer ensures that when the light bulb is replaced, the fitting does not loosen / rotate from the threaded end to which it is attached.
interne diameter: M13 (of wel 1.3 cm)
|Material:||metal - galvanised|
|Dimensions (cm):||Inner Diameter: 1.3 cm (0.51 inch)|
|Thickness / depth (cm):||0.2 (0.08 inch)|
|Outer Diameter (cm):||2.0 (0.8 inch)|