Philips Hue Outdoor Sensor review: Trigger Hue lights and HomeKit gadgets with this $50 sensor - CNET
Amazon.com: Philips Hue Secure Smart Contact Sensor, Black - 2 Pack - Made for Indoor Doors and Windows - Requires Hue Bridge - Works with The Hue App : Everything Else
Philips - M2741A Sidestream CO2 Sensor monitoring supplies - Pacific West Medical
Hue Smart Window and Door Contact Sensor | Philips Hue
Amazon.com: Philips Hue Secure Smart Contact Sensor, White - 2 Pack - Made for Indoor Doors and Windows - Requires Hue Bridge - Works with The Hue App : Everything Else