I have just added to my Italian collection this "difficult to come by" Medium to Low voltage Insulator. This is a 2 shell cemented together insulator in the classis dark green glass. The "CA" indicates the wider groove on the top to handle the Aluminum wire. This insulator is rated @ 10KV's and was mainly used in Northern Italy (the age is about 70-80 years old).

I also have the older version manufactured by BORGO which is even harder to find: [id=255098410]