The keyring is a remove before flight style. 

On one side of the keyring is "The Battle of Britain A Harry Saltzman Production". 

The other side is the AI A squadron codes from Skippers Spitfire. 

The side featuring the logo utilises the logo seen as the film was being prepared/made and is the logo seen on the side of the B-25 Mitchell Camera shop and also all headed paper from the company. 

Size of the material is approx 13cm x 3cm.