X-Sense SMA11 Smart Mailbox Alarm with App Alerts

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Product guide

X-Sense SMA11 Smart Mailbox Alarm with App Alerts

The X-Sense SMA11 smart mailbox alarm uses a sensor and included base station to send app alerts when mail is detected. Its wireless setup, adjustable audible alert, and multi-user sharing suit households that want delivery notifications away from home, provided their Wi-Fi and mailbox are compatible.

At a glance

App push notifications for detected mail, with multi-user sharing and mail reminders.
The app offers one-button silencing, volume adjustment up to 100 dB, and ringtone selection.
Requires 2.4 GHz Wi-Fi and connects through the included SBS50 base station. It is not compatible with 5.0 GHz Wi-Fi.
Designed for curbside or post-mount, wall-mount, slot, and cluster mailboxes. Not suitable for mail slots without lids.
Manufacturer claims up to four years of battery life based on five triggers per day.
Listed IP65 rating and operating range of 14–140°F (-10–60°C).

Price

$29.98Save 25%

Reference price: ~~$39.99~~

Price checked: Nov 14, 2026

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Pros and cons

Pros

App alerts and shared access can keep household members informed when away from home.
A replaceable battery and included double-sided tape support wire-free installation.
Adjustable volume and ringtone let users tailor the base-station alert.

Cons

Setup depends on a 2.4 GHz Wi-Fi network and the included base station, so it will not suit a 5 GHz-only network.
The four-year battery-life claim depends on five daily triggers, so heavier use may not match that estimate.

Technical specifications

15 specifications

Identity
Brand	X-Sense
Model	SMA11
Sensor technology	Infrared Sensor

Connectivity and controls
Control method	App

Power and battery
Power configuration	Battery Powered
Battery chemistry	Lithium
Battery requirement	1 CR2 batteries required. (included)
Voltage	3 volts
Listed capacity	1000 milliamp_hours

Sound and range
Audible noise	100 db
Maximum range	50 meters

Dimensions and installation
Mounting type listed	Protruding
Dimensions	3.91"L x 1.02"W x 1.06"H

Compatibility and environment
Compatible devices	Smartphone
Color	Basic

What to know before buying

The alarm is stated to be unsuitable for mail slots without lids. Confirm your mailbox has a lid and can accommodate the sensor.
The stated Wi-Fi requirement is 2.4 GHz only. Customer feedback reports both successful connections and difficulty connecting the base station, so setup may warrant attention.

Listing details to confirm

Listing details conflict or remain unconfirmed: the title and core model identify SMA11, while the package list names a Smart Mailbox Alarm SMA51. The listed size says “1 Alarm + Base Station,” but the explicit media list names the base station, manual, and SMA51 alarm. Confirm the selected listing's alarm model and exact package contents before ordering. The battery claim is based on five triggers daily, and the 50-meter range is a listed maximum rather than a guaranteed site range.

Who is it for?

A good fit for

People who want app notifications when mail is detected, including when they are away from home.
Households that can use a 2.4 GHz Wi-Fi network and want to share alerts among users.
Owners of compatible lidded curbside, wall-mounted, slot, or cluster mailboxes.

Less suited to

People with only 5 GHz Wi-Fi available.
Mail slots without lids.
Buyers who need a confirmed SMA11 alarm in the package without checking the listing's conflicting SMA51 package entry.

X-Sense SMA11 Smart Mailbox Alarm with App Alerts · photo 2 — Additional product photo 2

Customer reviews on Amazon

4.3 / 5 · 1,714 ratings

5 stars72%72%
4 stars9%9%
3 stars5%5%
2 stars4%4%
1 star10%10%

Customer feedback highlights easy setup, timely phone alerts, and useful range, including one reported 360-foot connection. Some customers describe a doorbell-like sound, while others report difficulty connecting the base station to Wi-Fi and say the instructions are hard to read. These reports matter because the alarm relies on the included base station and 2.4 GHz Wi-Fi, while its listed 50-meter maximum is not a guarantee for a particular property. Aggregate ratings lean positive overall, but a notable one-star share cautions against assuming setup or reliability will be consistent.

Positive themes

Customers describe setup as easy and report useful real-time delivery notifications.
Some customers report good range and a doorbell-like audible alert.

Negative themes

Some customers report substantial difficulty connecting the base station to Wi-Fi.
Customers criticize the instructions as difficult to read because of their small print.

Mixed feedback

Connectivity and reliability receive mixed feedback, with reports of both trouble-free use and connection problems.

Frequently asked questions

Does the X-Sense SMA11 work with 5 GHz Wi-Fi?

No. The listing says it is compatible only with 2.4 GHz Wi-Fi and connects to the X-Sense Home Security App through the included SBS50 base station.

Which mailboxes can use this alarm?

The listing names curbside or post-mount, wall-mount, slot, and cluster mailboxes. It says the alarm is not suitable for mail slots without lids.

How long is the battery life?

The manufacturer claims up to four years based on five triggers per day. Actual use may differ with trigger frequency.

What comes in the package?

The listing has inconsistent model details. It describes one alarm and a base station, while its media list names an SBS50 base station, user manual, and SMA51 alarm. Confirm the selected listing's package and alarm model before purchasing.