55 ringtones for your choice, easily customizable. To change ringtones, simply press the plus or minus button to change, then press the volume button for 5 seconds when you hear "ding" and press the push button to match the melody. 5 levels for adjustable volume (from "mute" to level 4), choose the volume you need for the time, such as a low volume to avoid waking everyone in the morning or disturbing the baby's sleep, high volume, if you live on the second floor or for a large place. The distance between the receiver and the transmitter can be up to 300 meters. With wireless connection technology (connected by radio) and IP55 waterproof level, it allows you to choose the location of the transmitter and receiver anywhere you need, such as the front door, workshop, apartment, old house, dormitory, mailbox, office, etc. It is also a very ideal replacement for the traditional bell that has failed and an alarm for elderly patients and nurses. This wireless doorbell is easy to install and