The prime reason for mis-fuelling is that the diesel pump filler nozzle is larger than the petrol nozzle.
 
So, both the petrol and diesel filler nozzle will fit.

Diesel Key has been discontinued - replaced by Diesel Fill which is more robust device  which fits a greater number of vehicles.  
 
We only have Diesel Fill for vehicles with screw-on type fuel caps but hope to extend this to bayonet type fuel cap fittings in the near future.  If you have a screw in fuel cap and the filler neck does not have a flap Diesel Fill should fit your vehicle.
 
******Applications are vehicle specific so before you purchase this please contact us in order to check the compatibility of the Diesel Fill in your vehicle. 
 
*The Diesel Fill Cap may not work with aftermarket long range tanks. 
 
**ALL PICTURES SHOWN ARE FOR ILLUSTRATION PURPOSE ONLY.ACTUAL PRODUCT MAY VARY DUE TO STOCK AVAILABILITY.