The RAC Helmet can be found in two marks, the distinguishing feature being that the Mk II has the removeable liner with the 'Lift the Dot' centre fastener.
The Chinstrap comes in three marks, the first being the complicated internal spring and elastic version seen on early British and all Canadian Mk II helmets. The second Mk II version is all elastic and can be found in either khaki drill or on later versions olive drab and finally there is the Mk III version with the quick release.
Here is a Mk II RAC Helmet with a Mk II Chinstrap in khaki drill.
Here is a Mk II RAC Helmet with a Mk II Chinstrap in olive drab. Many of these saw post-WWII service with the RN and used to be very common.
Here is an example of a Mk II RAC Helmet with a Mk III Chinstrap.
Here is a Canadian Mk II Helmet with a Mk I Chinstrap.
