This is a metal spring washer with an inner diameter of 1.0 cm / 0.39 inch (M10). We use these spring washers for example between the fitting and the lampshade (see photo). In this case, the spring washer ensures that when the light bulb is replaced, the fitting does not loosen from the cap or rotate, causing a risk of damage to the electric wire. Not to mention the fact that it is annoying that it is difficult to get your light bulb out of the socket when everything turns.
interne diameter: M10 (1.0 cm)
|Material:||metal - galvanised|
|Dimensions (cm):||inner diameter: 1.0 cm / 0.39 inch|
|Thickness / depth (cm):||0.2 (0.08 inch)|
|Outer Diameter (cm):||1.4 (0.55 inch)|