52 Songs, 4 Volume Levels: This wireless doorbell has 52 melodic ringtones from around the world, which can be changed with the push of a button. This product has four adjustable volume levels (including silent mode), and also has a blue flash, silent mode flash always lights up to meet your different needs. 400 Meters Range: The wireless signal can be transmitted in a super long range of 200 meters (in open area), and at the same time the signal's ability to penetrate the wall is good, the signal can completely cover your home without interference from other devices. Memory Function: This wireless doorbell automatically saves the ringtone and volume you set, and automatically restarts after an accidental power outage or after being unplugged and turned on again, without you needing to reset it to your preferences. Waterproof and Dustproof: With IP44 waterproof and dustproof function, it can ensure the wireless doorbell can normally be used outdoors. The working temperature is from