no damper felt backing

[Tvak@AOL.COM]

List,

Still searching for damper felts for an old no-name piano ("rose by any other 
name").  The only ones I can find that are narrow enough have no red felt 
backing.  

OK... What's the purpose of that red felt backing anyway?  I'm going to buy 
these felts, because they'll fit, but I'm curious as to the negative factors 
of having damper felts that are not backed.

Thoughts?

Tom Sivak