Non-Manufacturers' Packaging.

In the 1960s there was a joint promotion between the Mobil Oil Company and Lesney Products. Yesteryear models were packed in red Mobil Oil window boxes.
The models generally associated with Mobil boxes are Y2 Renault, Y5 Bentley, Y6 Bugatti (either colour), Y8 Sunbeam & Y10 Mercedes. Some references include the Y3 Benz. Initially only the Bentley and the Mercedes were issued, but such was the popularity of the promotion other models were used. In the end the Mobil packaging ran out, and some 1st series models in normal boxes (Y1 Allchin was one) were given out. The albums for the cards had a redemption slip in the centre.