Blue 15W incandescent golfball (round) Colourglazed style light bulb with a BC-B22d bayonet (22mm) cap.Colourglazed light bulbs have a internal coloured coating which will not wear away and provides a strong and vibrant colour. These light bulbs are vacuumed filled so are ideally suitable for indoor and outdoor use.Please note that even though the light bulb itself is IP65 rated, it must be used in a suitable IP65 rated socket in order for it to be used outside safely.Need more help in choosing a suitable light bulb? Read our guide What is a Golfball Light Bulb.