|The MGA With An Attitude
SPOTLIGHT COVERS - AT-129
It is common to see accessory plastic covers or cloth socks for the spot lamps. The picture at right is typical, although they may come in hundreds of colors, patterns, logos, and various materials. They are also available for almost any size or shape of spotlight ever manufactured. Aside from being cute and protecting the lamps, there is also a legal requirement driving the market.
One legal issue with accessory spotlights is the modern requirement to dip the bright lights for oncoming traffic, applicable world wide (to be discussed elsewhere). Another issue is certain limits on lamp power. I believe 100-watt headlights are illegal in Illinois, possibly nation wide in USA and Canada (not sure about other countries). Such high power lights can only legally be used off road. Not only that, but those lamps must be covered any time the vehicle is on a public road way. As such, the market for these things is sort of mandatory along with their use. The covers will often be included with the purchase of high power driving lamps (a great opportunity for the manufacturer's advertising).
Back the clock up 40 years or more and the lamp covers were not so common, used primarily to protect expensive lamps when not in use, and maybe not a legal requirement. Vintage covers may also be hard to find and possibly only in bad condition. Round covers are generally easy to buy, as they will work for almost any round lamp in a few standard sizes. Also round is very common for vintage lamps.
For those so inclined, there is (was) a pattern and plans to make your own driving lamp covers. The link has since failed, so you're on your own to be creative. Take a hint from the picture.