TR2-6 petrol cap locking, round. TR2-3B owners will need to purchase a grommet 650247.

This original product, manufactured by Wilmot Breedon, locking petrol cap is supplied with two keys.

Cap & fitting sleeve of 2" outside diameter. 

These are original product  and are showing some signs of age regarding some of the plaiting in the inside of the the filler pipe. The price reflects the product condition.

This part is listed on the following page of the website, where further information and background reading may be found.

Fuel and braking systems » FUEL CAPS AND FILLER HOSES, SEALANT