DW tom mount question

I was wondering if anyone knows what (if anything) this feature does on the tom mount.
If you click the link its called SP435. On my kit it looks like a clamp of some sort, it opens up like a clamp but I am not sure what it could hold.
http://www.dwdrums.com/images/info/schematics/BassDrumMount/DWCP9900BD.pdf

This is what it looks like normally: http://www.interstatemusic.com/webapp/wcs/stores/servlet/product_107184

Thanks

It can hold a cymbal arm attachment.

Dennis

This is the reply I was hoping for.
Thanks Dennis!