The E-30-PT is designed to provide quick and reliable communication in noisier areas. The mic sensitivity is set to a low level until the TALK button is pressed then it is raised to a normal level. In this way, the E-30-PT assures that the called party's voice will be broadcast over the speaker. In applications where the background noise can be louder than the person calling, a handset type phone is recommended. Package Contents: E-30-PT Intercom Sub Station Plastic Rough-In Box Spade Terminal Flat Head Hex drive Screws Product Type: Intercom Sub Station Product Type: Intercom Sub Station Manufacturer Part Number: E-30-PT Limited Warranty: 2 Year Manufacturer: Viking Electronics, Inc Product Model: E-30-PT Product Name: E-30-PT Intercom Sub Station Brand Name: Viking Electronics Brand Name: Viking Electronics Height: 5 Width: 5 Depth: 2.3