1. Adopts full-duplex voice intercom communication technology, automatically recognizes and processes voice signals, and does not require any operation during the call. 2. Dedicated sidetone processing chip with automatic squelch function, which can effectively improve howling. 3. Using automatic call control technology, the external microphone and speaker are integrated to achieve a single-line connection with the host. It's easy to install. 4. Comprehensive application of experience in electroacoustic technology and selection of electroacoustic device designs with excellent performance. The output power is as high as 3W, the sound is clear and loud, and the voice resolution is high. 5 The main unit is designed with independent internal and external mute switches, which can be easily controlled to meet our needs. Features: It adopts full-duplex voice intercom communication technology, automatically identifies and processes voice-specific sidetone processing chips, and has an automatic squelch function, which can effectively improve howling. Using automatic call control technology, the external microphone and speaker are integrated to achieve a one-line connection with the host. Easy to install. Comprehensive application of electroacoustic technology experience and the selection of electroacoustic device designs with excellent performance, the output power is as high as 3W, the sound is clear and loud, and the speech resolution is high. The main unit adopts independent internal and external silent design switches, which can be easily controlled to meet our needs. Can output both internal and external sound signals (with bank teller recording). Using stereo jack output mode, the recording function is not controlled by the power switch and various function buttons. The main unit is designed with cable protection to prevent damage to the connecting plug. The extender can be hung on the wall or attached to the glass with strong tape. Application: banks/securities/hospitals/stations/places where anti-theft glass is installed. Specifications: Material: Metal + Plastic Color: As shown in the picture Product plug: American plug, European plug (optional) Voltage: 110-240v Working voltage: DC12V Maximum working current: 1A Main and sub speakers: 3W External microphone: -38db3db Built-in microphone: -38db3db Size: 18.2*13*5.6cm/7.2*5.1*2.2in (main unit) 6.1*8.5*2.4cm/2.4*3.3*0.9in (auxiliary unit) Packing size: 15* 12*4cm/5.9*4.7*1.6in Accessories: suitable for banks/securities/hospitals/stations, etc. Especially where anti-theft glass is installed. Package includes: 1*Internal host 1*External speaker 1*Power supply 1*Instruction manual Note: 1. Please allow 0-1 inch error due to manual measurement, thank you for your understanding. 2. Please note that the new model and old model of this product will be sent randomly, and make sure you don't mind ordering before.