This Ring (crown wheel) and Pinion set that is for MGA, MGB Banjo axle (1962 to 1967), with a ratio of 3:90 to 1 suitable for driving.  This is a brand new unit of recent production. The discoloration in the pictures is the preservative grease added at the factory. These have no corrosion. No machining will be needed to install this as it is a standard MGB Banjo Axles assembly. Made in Germany for a perfect fit.   Free shipping to the US. International bidders please ask for a shipping price before buying.