The mailing, which was created by TBWA\GGT, comes in a long envelope, which carries the line: "Shopping for a new estate? Here's why you should put us on your list."
Inside is a 170cm-long till receipt, which aims to demonstrate how much more space a Vectra Estate offers compared with rivals in its class.
At different points along the receipt, hand-written comments in red mark the amount of shopping the Volkswagen Passat estate and the Ford Mondeo estate can carry.
Matthew North, the senior account director at TBWA\ GGT, said: "What makes this piece so compelling is its physical demonstration of the fact that the Vectra has got bags more room than any other estate in its class."
The pack also includes a glossy leaflet that folds out to reveal pictures of the inside and outside of the car. Writing on the front of the leaflet above the picture of the exterior reads: "The new Vectra Estate. 2.2 litres in the front." On the inside of the leaflet accompanying the pictures of the interior are the words: "1,850 litres in the back."
The campaign was written by James Sexton and art directed by Pete Jones.