Offered here is a 1970s large Cartier Tank Sleeper, rectangle case watch in a 20 micron electroplated case.
These early Cartier electroplated case models where made differently than the later ones signed must de Cartier.
This RARE model has a large and very appealing size measuring 27.7 mm across by 37.5 mm in length.
It is one of the three versions: New York, Paris, London. This one is the Paris version.
The dial on this watch is original and signed only with Cartier. Most Cartier watches with Cartier only on the dial have solid gold cases. So when you wear this watch no one will know it is not a much more expensive solid gold model.
The dial is white with large Roman numerals. The hands are blackened steel and original as well.
The bezel is stepped and very wide.
The mineral crystal is slightly domed and appears to be original factory made.
It has a few small scratches that are very difficult to see with the naked eye.
The winding/time setting crown is also original Cartier with the blue stone center.
The case back is of a snap back type.
The text on the back cover reads as follows:
The movement used here is the mechanical ETA 2512 17 jewels signed Cartier.
The 18K gold plating is in a remarkable state for the age of this watch.
Only wear appears on the very edges of the case cover and one small spot on the case cover back, about 1 mm in size. 
The black band is original Universal Geneve of that period. The buckle is a generic one.
We can supply a solid 18K gold buckle at an additional charge if needed.
We clean the inside of the leather bands with alcohol prior to shipping.
The watch will fit up to a 7 inches wrist.
If you need to replace this band look for one which measures 17 mm at lug end. The watch is running fine.
If you like to wear it often you may want to get it serviced for better precision.
This is a rare and collectible Cartier watch. Just Google it and you will see.