The Snom 4011 D7 Expansion Mod D715 D725 D765 D7BK is a VOIP phone product designed for enterprise networking and IP PBX systems. It is manufactured by Snom and has a model number of D7BK. This expansion mod includes various components and features to enhance the functionality of the Snom D7 series phones. It is a reliable and high-quality product that supports connectivity through USB interface. With its compatibility with different Snom models and specific features such as regula, park, and intercom, this expansion mod is a valuable addition to any business communication system.