Feature 1The frequency of use of this product is in accordance with national regulations and will not cause harmful electromagnetic interference, which is universal worldwide. 2Outdoorbell is power supplied by 4pcs AAA battery (not included), easy to replace the battery. Indoorbell is used with an external USB data cable. 3Low power consumption, long standby time for outdoorbell up to 4 months. 4Big and adjustable speaker, clear voice, can be used as mobile interphone. 5Long working distance, the maximum open distance can reach 200m / 656.2ft. 6Easy installation, stick directly to the wall with adhesive tape. 7Outdoorbell pair with indoorbell by learning its code, 1 outdoorbell can paired with 2 indoorbells and no interference each other. 8Made of high quality ABS plastic, exquisite and small, beautiful and high grade.SpecificationCondition: 100% Brand NewItem Type: Door BellMaterial: ABS PlasticColor: As Pictures ShownOutdoor-Bell:Voltage Range: 4 x AAA batteries (not included)Working Temperature: -20-55Transmission Distance: Approx. 200m / 656.2ft in the open, 5 - 50m / 16.4 - 164ft in obstaclesWorking Frequency: 467.6375MHZWorking Time: 4 MonthsWaterproof Level: No Waterproof FunctionIndoor-Bell:Voltage Range: 5V 1AWorking Temperature: -20-55Transmission Distance: Approx. 200m / 656.2ft in the open, 5 - 50m / 16.4 - 164ft in obstaclesWorking Frequency: 467.6375MHZWaterproof Level: No Waterproof Function .wang-edit-text{ font-family:'Arial' important; } .wang-edit-text table { border-top: 1px solid 000; border-left: 1px solid 000; } .wang-edit-text table td, .wang-edit-text table th { border-bottom: 1px solid 000; border-right: 1px solid 000; padding: 3px 5px; } .wang-edit-text table th { text-align: center; }Package List1 x Outside Doorbell1 x Inner Doorbell1 x Screwdriver1 x Manual2 x StickerNotePlease note that the new type and old type of this product will be sent randomly, and make sure you will not mind before ordering.