Long Range & Stronger Signal: Works within 300 meters in open space, this doorbell's signal penetrates obstacles very well. You can connect the receivers anywhere you want in your home. No wireless interference problem. Super Easy Installation: The receiver does not require any assembly or batteries, just plug in with an electrical outlet. The transmitter can be fixed to the front door with the included screws or stuck to the door with the included sticker. IP68 Waterproof: The transmitter is IP68 waterproof and perfect for outdoor use. IP68 is the highest waterproof level. It is fully sealed with silicone. Keeps against dust, rain and high temperature. Energy Saving & Long Life: Low power consumption design, energy saving and durable in use. The transmitter battery can be used for up to 3 years. The transmitter can withstand more than 100,000 times of click. Large Powerful Speaker: Thanks to the large speaker of 40 mm diameter, this doorbell has a very pleasant sound with 5