The eTiger S3b-S GSM alarm system consists of 2 motion detectors, 2 window/door sensors, 2 remote controls, and 2 NFC tags. You can expand the set to include up to 50 sensors of your own choosing. When the system detects something, it'll set off the integrated alarm with a 100-decibel audio signal. You'll then receive a notification via an SMS, a push notification via the app, or a phone call. You can configure up to 10 phone numbers that you want the system to notify in the event of a threat. It's also possible to enter a phone number on the control panel, which can be useful if you're not carrying your phone with you. It's easy to switch the alarm on or off with the remote control, NFC tag, or the smartphone app (iOS and Android). The alarm system uses AC power and has backup batteries, which can be useful in the event of a power failure.
Note: this alarm system uses a SIM card, which must be purchased separately.