105-0373-01 - Reference Number 18A - Rear Cover, Fits All 2003 and 2004 Models, Fits SOME 2005 Models.

Part Number 105-0373-01 - rear cover, fits all 2003 and 2004 model year 420's or 425"s, fits 2005 model year 420's and 425's with serial number between 250000001 through 250000400.