All Berg's flat tube radiators are equipped with louvered style fins. The louvers are small slats punched thoughout each fin. This allows the air to pass through the fin, maximizing heat transfer and boosting the core efficiency to the highest in today's market.
The high cores (1923-1927) measure approximately 18 3/8 inches header to header, which is just the exposed portion of the fins.
The low cores (1917-1923) measure 17 inches header to header.