The Opel Manta A series, here in the UK at least, was supplied with these quite heavy duty engine sump guards as standard.

They are quite an unusual item to find fitted to a road car, but maybe the engineers at Opel thought it essential to protect the bottom of the engine and keep water from flooding into the alternator. Typically they are removed for servicing and don't get replaced. As they are made from regular mild steel and given the location where they are mounted, they are quite prone to rusting away.

This one I had powder coated in a silk black finish some years ago, it is out of my loft and is now up for grabs

Opel Manta sump guard - the dips are spot welds

Opel Manta sump guard - looking clean from above

Opel Manta sump guard - some denting is inevitable

Opel Manta sump guard - a few tiny rust pinholes