Feature(may vary by option.)

●🔔 【58 Melodies & 5 Volume】Wireless door chime features 58 chimes and 5 levels adjustable volume(0 dB to 110 dB) to meet your needs for different occasions. Remembers your last melody and volume level after a power outage; no need to reset to your previous settings.
●👍 【Door Entry Window Open Alarm】 BITIWEND door chime can be used as an alarm to remind businesses front door when burglar opens door and helps deter break-ins. Perfect for family which has children or elders.
●🌐【Up to 600 FT Working Rang】 Wireless door sensor chime with working rang up to 600ft in open area to cover your house or store, ensures you will never miss a visitor. Note: The battery level will affect the signal receiving range. It is recommended to change it once every 12 months.
●🔔【Expandable】Each door sensor or receiver can be expandable,you can use them with additional BITIWEND door sensors or doorbells. You can install them in your dining room, bedroom, living room, garage, yard, or your store and office.
●🔧【Easy to Install to Use】 Just plug the doorbell receiver into any standard outlet and tear the double-sided adhesive tape on the back of door sensor(or screw mounted) to stick to the door or window, please take the insulating paper away before using the sensor.

[1chime Receiver-1door Sensor]