Sun-tans are a bit controversial. They are often considered to be a sign of beauty and health (for "white" people), but, technically, the body only creates a tanned appearance as a defense against damaging ultraviolet radiation in sunlight. You don't NEED a tan to be healthy.
upon the skin has two main effects. One is that it manufactures pigments to absorb/block UV, as stated. The other is that the body uses solar energy directly to manufacture Vitamin D. It is observed that "black" people living far from equatorial climes tend to have a problem making enough Vitamin D. Sunlight is less intense there, and their skin pigmentation, which is Naturally sufficient to block higher-intensity sunlight in equatorial climes, interferes with letting enough sunlight through, to make enough Vitamin D, at high latitudes.
So, Too Much of a Good Thing (like skin pigmentation) CAN be a Bad Thing, depending on the situation. Nothing new there, especially when it can be pointed out that too much sunlight can also cause skin cancer. One reason for "white" people to GET sun-tans is to acquire some defense against that sort of thing, but one should try to do it in easy stages, not all at once. That means, don't stay out under the sun all day long! (Even "black" people can get sunburned; it's just not as obvious.)
The Even Tan Suit is for anyone seeking an "even" or "all over" tan, outside of a tanning parlor. One common way to do that is to simply sunbathe in the nude, but there are times and places where people don't want to do it that way, so an alternative is needed. This Idea is that alternative.
The needed technology is derived from observations of such things as microwave ovens and thermal "window tints". In the first, we see that the door of a microwave oven has a piece of thin metal full of small holes. Visible light can get through the holes, but longer-wavelength microwaves are too big, and stay in the oven. In the second, a window is given a thin reflective coating. Visible light can mostly get through, but longer-wavelength infrared radiation is too big, and gets reflected.
So, what we need is to extend this logic just a bit. A slightly thicker reflective coating will mostly let short-wavelength ultraviolet light through, and reflect longer-wavelength visible light.
The Even-Tan Suit, therefore, is quite a shiny-looking thing! It is a very thin layer of plastic that has JUST the right amount of reflective coating applied to it. When wearing the Even-Tan Suit, cultural mores regarding body-modesty can be satisfied, and an all-over tan can still be obtained.
Caution: because the material of the Even-Tan Suit is so thin, it canot be expected to be particularly tough, and so it should not be subjected to excess stress. Think of it being delicate like temporary paper clothing.
On another hand, because so little actual material is involved in making an Even-Tan Suit, it should not be hugely expensive, either.