These are the internal braces for the 1801's.

I like the insides of the speakers to look nice. Rounding the edges of the cutouts over on the braces not only looks appealing it helps prevent chuffing inside a ported enclosure by allowing the air to flow over the edges in a more efficient manner.

You know, I never have enough clamps, no matter how many I buy I always find a way to fit more on the piece I'm clamping.