TP appears, somewhat unbelievably, to have opined:
Putting in a new counter top, on a built in desk. Walls on back and
sides. Old top had a large hole to run wires down to the computer,
power, etc. I would like to leave the top approx. 1 ½ inches away from
back wall to easily drop wires down. I’m looking for some suggestions
on a material to fill that gap? Something like foam or rubber that could
easily be slit, and a wire could be fed thru it. Any suggestions?

Thanks
TP

Jere's one that's 12 inches long. I guess you could combine several.....

http://www.rockler.com/ecom7/product...erings_id=5386

--
I sent ten puns to all my friends hoping that at least one
would make them laugh.
Sadly, no pun in ten did.