These are beach or even garden wear made of very lightweight material, They are actually see-through but the eye is distracted by the bold camouflage-style patterns and doesn't see the anatomical detail behind. This trick gets less effective the closer you get and can be upset by some lighting conditions.
They are so light that it feels almost like being naked, and sunlight is supposed to penetrate enough to tan effectively. The lightest type are equivalent to about a sun factor 4 and the slightly heavier type to sun factor 10. In theory, application of the same factor sunscreen to the rest of the body will give a uniform tan, though this will need some attention to the position of seams and hems. In practice, so far, I have found them not to give as good a result as proper nude sunbathing, the shape of the shorts being visible on the skin; I need to try more carefully before giving up on this.
So I'm not sure about their use for preventing white bits when you can't undress properly, but they are excellent for the lightness in feel.
They are very expensive. Mine came from http://www.galaxy-trading.freeserve.co.uk. You can buy four or five pairs of light trunks or shorts in a chain store for the price of these.
There are also tan-through products available from Kiniki. These are made from "Transol" which is another very open material, again relying on the camouflage pattern to hide the fact that they are really see-through. These are the Hot Leopard pattern:
The playing card shows how transparent they are. I don't know yet whether these work any better. They claim to let up to 80% of UV through, which would make them equivalent to a sun block factor of nearer 1 than 2. They are however very expensive; this style was on special offer at 30GBP. They weigh 38 grams.
©2007 nib -
2007-12-14 -> 2010-11-01