Features: 1.Streamlined design, the main unit is made of aluminum alloy, strong and durable. 2.Single cable connection, easy installation. 3.High quality loudspeaker for main unit and extension, high sensitive microphone for two-way intercommunication. 4.Simple to operate. No need to press any button to achieve auto two-way intercommunication. 5.Double-track adjustment with indicating light with spare audio jack. Specification: Two-way voice intercom counter interphone adopts auto dual-way intercommunication technology, automatic indentification of processing speech signals during a call dose not require any action, ideal for the bank, securities, hospital, bus station etc._x000D_ _x000D_ Features:_x000D_ _x000D_ Streamlined design, the main unit is made of aluminum alloy, strong and durable. _x000D_ Single cable connection, easy installation. _x000D_ High quality loudspeaker for main unit and extension, high sensitive microphone for two-way intercommunication. _x000D_ Adjustable volume with independent switch. _x000D_ Simple to operate. No need to press any button to achieve auto two-way intercommunication. _x000D_ Double-track adjustment with indicating light with spare audio jack. _x000D_ _x000D_ Specification:_x000D_ Working Voltage: DC12V_x000D_ Plug: US 110-240V_x000D_ Max Working Current: 1000mA_x000D_ Main Sound (sub sound): 2W-2W 100Hz-12KHz_x000D_ Outside Microphone: -42Db_x000D_ Inside Microphone: -42Db_x000D_ Audio Output: Dual-way _x000D_ Main Box Size: 15.8 * 8.7 * 4.6 cm/6.2*3.4*1.8in_x000D_ Deputy Box Size: 7.8 * 2.0cm/3.1*0.8in_x000D_ Package Weight: 678g/23.9oz_x000D_ _x000D_ Package List:_x000D_ 1 * Dual-way Counter Interphone_x000D_ 1 * External Speaker_x000D_ 1 * Power Adapter _x000D_ 1 * User Manual