Samsung BabyView SEW-3057W User Manual page 4

The transmission range of the wireless signal may weaken if heavy
obstructions such as a concrete, brick, or metal walls are between the
camera and monitor, or if there are several Wi-Fi routers and devices in
your environment.
To avoid interference wifh RF signal, keep your cell phone at least 3ft
away from the Camera and Monitor.
CAUTION
Risk of explosion if battery is replaced by an incorrect type.
Dispose of used batteries according to the instructions.