Fits all 123 chassis from 1977-1985. This is the Oil pressure plastic hose that goes from the back of your oil sending guage on your instrument cluster to the oil filter housing. If your oil pressure line fitting gets damaged or if it is leaking, it is time to replace! No instructions at this time, but this is a pretty straightforward job. If you havent removed your instrument cluster before check out our manual on the ins and outs of removal and replacement.