They are for looks somehow lol.
Some people say they drip sometimes so use that as an excuse I guess.
I have never had any of mine leaking out so no need for sweatbands on mine..

 

the wristband ones are based on track cars that use them to absorb any leaking fluid that can occur in racing conditions. Leaky fluid in racing conditions can create issues. For street driven cars they are only really for looks for the most part as you rarely see leaks in daily driving conditions. I don't like the look of the spoon blue ones, I prefer the Mugen orange version. They are supposed to be fireproof material fwiw, one size fits both caps. Overpriced jdm, but I still like em. Here's a pic with the mugen ones

https://www.s2ki.com/forums/index.php?showt...&#entry11865812