The popularity of swim briefs---then and now

[Torchwatch]

The expensive jammers are made from sharkskin fabrics that move through water with less drag than naked skin, the full body sharkskin suits were banned as giving swimmers an unfair advantage.
Lycra jammers have more drag then naked swim and therefore make you swim slower.
You even need instructions on how to put expensive jammers on :
https://www.youtube.com/watch?v=bvQ1LEPYcxU