100% SATISFACTION: Our AVANTEK wireless doorbell is approved by FCC, CE and RoHS; we provide customer service on our products and we will always do our best to support you. HIGH PERFORMANCE TRANSMITTER: Ultra-low power consumption; uses a lithium battery that boasts 3 year maximum lifespan; IP55 dustproof and waterproof; working temperature ranges from -4 °F-140 °F; withstands various harsh weather conditions 1000 FT ULTRA LONG WIRELESS RANGE: 2 plug-in receivers included; will not interfere with other equipment in your home or those of your neighbors; ensures you will never miss a visitor, even if you are a few rooms away or on another floor 52 CHIMES TO CHOOSE FROM: 1.1 in (29 mm) stereo speaker delivers rich and crisp sound; 5 adjustable volume levels with a maximum setting of 115 dB; press Next or Previous button to easily choose from 52 melodies MEMORY FUNCTION: Remembers your last melody and volume level after a power outage; no need to reset to your previous settings; convenient and easy-to-use design for an enhanced user experience EASY TO SET UP: Can add more AVANTEK RB-1/CR-1 receivers for increased coverage; includes 2 screws, 2 anchors, 1 key and 1 adhesive patch for easy installation of transmitter Mini Yet Mighty We have re-designed this receiver, giving it a mini size of just 2.8 x 3.1 inches, so that it won’t block off any neighboring power sockets. The performance, however, has not been compromised. A huge selection of 52 melodies allows you to easily choose one that suits you. The Next and Previous buttons allow you to go back and forth when choosing a tune, meaning you do not have to cycle through the full list again if you accidentally skipped the one you wanted. Durable and Waterproof Transmitter The built-in lithium battery has an ultra long three-year lifespan, saving you the annoyance of frequent purchases and replacements. The impressive IP55 dustproof and waterproof rating makes the transmitter tough enough to withstand various outdoor environments. And with a working temperature ranging from -4 °F to 140 °F, the transmitter can work for you in even the harshest weather conditions. Long Operating Distance The doorbell supports an extensive 1000 ft working range (depending on the operating environment). Rest assured that you’ll never miss any important guests or urgent deliveries again with the help of this doorbell. Innovative Memory Function One of the great advantages of the AVANTEK Doorbell is its memory function. Every time you turn on the device after a power outage, it remembers your last-set melody and volume level. Note: Metal will interfere with the signal and shorten the transmission range. Please place the transmitter in areas away from metals.