Solex 2-Barrel Air Filter

[twautomotive]

I looked in my parts book and this air filter is listed for the Series III and Series IV Alpines with the Solex 2-Barrel Carburetor. Were these really stock? I've only seen the "bat" air filter on a Series III GT and the "rock" strainer types on a Series IV. Any help will be appreciated.
Tom

 

[alpine_64]

Ive seen these on Australian delivered alpines and rapiers and similar on other period rootes cars.. Maybe for wxport markets with dusty conditions.

I knwo there was another filter used on the S3 GT when it went to compound solex that had a small mental filter top that fed a large canister style filter housimg like the batwing used