The Smart Outdoor Camera with Siren comes with an alarm - a built-in Outdoor Siren, whereas the Smart Outdoor Camera does not. All the other features of the Outdoor Camera with Siren, such as the outdoor light, motion detection, night vision, easy installation, real-time alerts, etc. are similar to those of the Smart Outdoor Camera (except for the alarm mentioned above). These smart home security cameras are compatible with Amazon Alexa, Google Assistant and Apple HomeKit. The RRP (incl. taxes) of the Cameras differ, however both are available with free delivery on the Netatmo shop.