z-bar question?

http://http://cgi.ebay.com/ebaymoto...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

Can someone please explain what the second round hole is for on this bracket. Thanks D.B.

:burnout:

Link doesn't work. at least not for me.

Do you mean the Z bar braket that goes on the frame??????