Tighten mids and lows

Increase low frequency responses

Easy adjustment to ensure accurate coupling

Allow "tilting" for imaging adjustments

Allows direct and rigid fastening to your speaker

3/8" thick steel provides mass loading

3/8" thick steel eliminates "ringing" common to lighter steel or tubing.

Increase speaker footprint

Increase speaker stability

Protects bottom corners from moving or vacuuming

And of course they enhance your speakers appearance!