The wire is to connect the cavities to the control cavity. Again, more useful in rear-route situations. You just run a wire from each pup cavity to the control cavity on the back. Then paint over it. Or with a tele style where the control cavity is not routed with the pickup cavities. ALSO! I left this out, too. Place a strip of tape that connects the pickguard to the control cavity. It just has to touch the shielding in the cavity and lay flat on the top of the guitar (not sticking out of the pickguard, of course) so that the shielding on the back of the pickguard touches it. I guarantee, opinion or not, this is the best way to do things. I'm not speaking as a person who's stuck in 'his ways' or happens to think that my way is right. Because it's not my way. I did it wrong forever until my eyes were opened by an amazing and well respected Builder and electronics guru. The best players in the world trust him (mike landau, claptscott henderson, eric on, mark knopfler...) to build their axes, amps and electronics. Fact is, it's the best shielding method. Not inferior but superior. It may be overkill, but it works...better than anything I've heard before. I'm no world class builder...but the man I learned from is the best -- hands down.