[Upgraded Mailbox Chime Alert]: Our newly designed mailbox sensor allows you and your family to avoid frequent trips to check mail during cold winter nights, reducing inconvenience and risk, saving time and making life more convenient. Additionally, the mailbox alert anti-theft feature helps protect your mail securely. [Enhanced Coverage and Expandable Pairing]: Mail alert receivers can operate up to 800 feet in an unobstructed area, ensuring you never miss a mailbox alert. It also supports pairing with multiple transmitters, suitable for homes and offices with multiple mailing points. [Instant Alerts and LED, Music Notification]: When the mailbox is opened, the receiver immediately emits a sound and lights up a blue LED, which continues to flash until the stop button is pressed. You can choose from three different alert tones to suit your personal preference for a more customized experience. [Easy Installation]: The mailbox alarm is battery-powered and wire-free for easy installation. It is compatible with various mailbox types, including standard, wall-mounted, and slot mailboxes, allowing you to easily adjust settings based on your mailbox type. Color: White Material: Plastic Package Contents: 1 set * Mailbox Alarm Only the above package content is included; other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture to appear slightly different from the real thing. Measurement allowed error is +/- 1-3 cm.