I picked up some edging grommet from Pegasus Auto Racing today. "Light-duty plastic strip fits 20 gauge sheet metal. These U-shaped nylon extrusions can be used to protect wires and hoses when they pass through holes in sheet metal or to cover a sharp edge of a metal panel. The flanges can be slit to conform to sharp corners such as the inside of a rectangular opening. Natural translucent white color." http://www.pegasusautoracing.com/ProductSelection.asp?Product=4308I cut slits in it so it would make the bends at the corners. It fits real tight but I might put some glue on it during final fitting.
This is the pass through for the Radios to the Intercom.
