CDL® is the USA trading division of Clark Door Limited, which has a long heritage of over 100 years. CDL is an independent co ... mpany that specializes in acoustic doors and industrial doors which are manufactured at our Carlisle base and are exported to over 40 countries. CDL specialises in supplying high quality, reliable acoustic doors to the entertainment industry, film studios, music venues, theater, cultural centers and many other industries requiring specialist, sound insulating and acoustic fire rated doors. For more information, visit www.cdldoors.com read more