Features: Automatic two-way intercommunication without pressing any buttons. Anti-interference, no noise, two-way audio recording output. The automatic identification process handles the voice stack number, and the call process does not require any operation. The side-sound processing chip has an automatic squelch function to effectively improve howling. Automatic call control technology, integrated microphone and speaker design of the external machine, and realizes one-line connection with the host, easy to install. Can output internal and external two-way sound signal (with bank counter recording), using stereo socket output mode. With recording function, independent of power switch and function button control. The auxiliary machine can be hung on the wall or attached to the glass by the distributed double-sided tape. Two-channel adjustment with channel dynamic indicator for easier use. The internal volume knob and the external sound knob can adjust the volume of the inside and outside respectively. The two green indicators N above the regulator during the intercom indicate that the host speaks, and the OUT indicates that the slave speaks. Specification: Condition: Brand New Color: Shown as Picture Material: ABS Maximum Working Current: 1A Main and Auxiliary Speakers: 3W External Microphone: -38db±3db Inner Microphone: -38db±3db Package List: 1 x Host 1 x External Machine 1 x Power Supply 10 x Adhesive 8 x Fixed Plate 1 x Instruction Manual . Note: Please note that the new type and old type of this product will be sent randomly, and make sure you will not mind before ordering.