You mean the breathstopper ? If you have the wool one then there is no need to buy the other. It's really bulky and hard to breath through.
Save your money.
I'm actually really interested in this;
686 :: Strap - Ombre Plaid
I used to have the 686 one...it wasn't as good as I'd expected. It was kind of awkward to fit on my face, but the real problem was the velcro. There is stitching that goes all the way around the edges, and the velcro on my mask snagged on it every time so whenever I removed the mask it pulled out more of the thread.
I returned it and got 2 Yowies instead. They're so awesome that when I'm about to put one on I get that same excited feeling as I get when I'm about to eat bacon!