Dual Way Voice Mic Speaker Intercom Window Counter Interphone for Security Company 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. Features: Streamlined design, the main unit is made of aluminum alloy, strong and durable. Single cable connection, easy installation. loudspeaker for main unit and extension, high sensitive microphone for two-way intercommunication. Adjustable volume with independent switch. Simple to operate. No need to press any button to achieve auto two-way intercommunication. Double-track adjustment with indicating light with spare audio jack. Specification: Max Working Current: 1000mA Main Sound (sub sound): 2W-2W 100Hz-12KHz Outside Microphone: -42Db Inside Microphone: -42Db Audio Output: Dual-way  Main Box Size: 15.8 * 8.7 * 4.6 cm/6.2*3.4*1.8in Deputy Box Size: 7.8 * 2.0cm/3.1*0.8in Package Weight: 678g/23.9oz Package List: 1 * Dual-way Counter Interphone 1 * External Speaker 1 * Power Adapter  1 * User Manual