Xtra Line metal wall light with socket for S14d bulb The Xtra Line wall light only becomes a complete light with the right bulb. The small metal base with S14d socket can be fitted with a suitable bulb up to 25 W and can be varied in appearance depending on the look and length or Form of the bulb. Not only can a strip bulb be inserted into the socket, other variations are also available so that the desired version can be selected depending on lighting requirements and taste.