Its the Ilitch routed in noise canceling system, presumably from the days Suhr installed them in their guitars. Very effective IMO. I've got an on/off switch and I really can't tell a difference in tone.
These days I don't think its necessary as Ilitch has the system adhered to a pickguard.
It is the Silent single coil system that suhr used to sell, you may have see it in a backplate form. This is the non backplate sytem , the one that suhr installed in their shop. It is , like the ilich NRS .. http://www.ilitchelectronics.com/lcncs/
It needs the body of the guitar to be routed for it.