glass in limb core

[SL]

Why do some bows have a single glass lam in the center of the stack? I know the bow was probably designed that way but what purpose does it serve? Seem like there are a lot of bows without the center glass as well. I've always been curious about that when it seem glass is so heavy.
SL

[Furtaker]

Some people use it as a color strip in their limb.
Others use it to gain stability.

[JamesV]

What Frank said, he nailed it

[Crooked Stic]

SL you are right too heavy. If you need glass in there to get stability then you need to rethink your design.