Vented Valve Caps???

[267ex]

I was looking at the powroll website and saw these things, ive never heard of them before and dont really understand how they work or wat they do really.

can somebody explain? and do you think its worth it?

http://www.powroll.com/P_HONDA_TRX250EX.htm

[LazeR]

ive never seen one of those before, seems like oil could get out too ? I understand the concept, doubt you would feel very much difference though