Roma double button down. The Roma double button down collar is a double layer collar like the Windsor double collar. This collar shirt is from Italian inspiration as mentioned in the name. It is a very extravagant and flamboyant shirt collar because of its height, its point length, its buttons on the points and of course double layer. It is a ‘must have’ for any fashion shirts addict. The Roma double collar is one of the Italian shirt fashion symbol. It can be worn with or without a tie.