Sonoff SNZB-04 Manuel D'utilisation page 7

Installation methods
1. Tear off the protective film of the 3M adhesive.
2. Try to align the mark line on the magnet with that on the transmitter during
installation.
3. Install them in the opening and closing area separately.
Make sure the installation gap is less than 10mm when the door or the window is
closed.
The device weight is less than 1 kg.
The installation height of less than 2m is recommended.
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