Is it possible it uses both Zigbee and Z-wave??
I might pick up a sensor tonight on my way home...
This is from their website:
How Iris Works
The Iris Hub captures signals put out by smart home devices. When you connect the Iris Hub to your home's broadband router, you're creating a net of devices that can talk to each other and pass messages to and from the hub. If you have WiFi, Iris can use that, too, for Iris compatible WiFi devices. The Iris Hub relays smart home device signals to the Iris cloud and from there they can be accessed and controlled via your smartphone or web-connected tablet or computer.
Iris takes advantage of multiple well-proven technologies: Z-wave, ZigBee and WiFi. Since different devices use different technologies, using these most popular technologies means Iris can control a broader array of devices than competitors. That's why it's so easy to add new devices to your smart home — Iris uses the technology appropriate for each device. Look for the "Works with Iris" logo on smart devices before you buy.
Your devices maintain contact with the Iris Hub, sending signals as required. If a device is triggered, for example a contact sensor triggered by a door opening, the device immediately sends a signal to the Iris Hub where it is sent to the cloud and processed based on instructions you have set up.
Iris uses the cloud to remember all your instructions and send each device instructions via Z-wave, ZigBee, or WiFi signal (depending on which protocol the device uses). When alerts are triggered, Iris can send email, text and voice messages to you and your designated contacts' smartphones, tablets, or computers.