Do you have a Festoon lighting set, but don't want to put a light source in every fitting? Then this stopper is the solution. You simply screw it into the fitting, just like a bulb. This protects the fitting from moisture and allows you to decide where you want the light to shine on the cable.
The Black stopper has an E27 fitting. It is 5.7 cm long and has a diameter of 3.5 cm.