Aqara RTCGQ11LM Guide De Démarrage Rapide page 5

* The recommended installation height is 1.2 m to 2.1 m. If the
installation height is below 1.2 m, the detection area will decrease; if
above 2.1 m, the detection area might have blind spots.
2.1m
Effective Detection Area — Side View
* Note that the lens should be aligned with the detection area when
installing, and placed or pasted as close as possible to the edge of a
table or cabinet.
Effective Detection Area — Top View
2m 4.5m
170°
7m