The sales pitch for them is:
Protect your family and belongings, and react quickly if smoke or fire is present in your home. Connect the Smoke Detectors to your Smartwares Pro Link, and receive notifications to your smartphone or tablet – wherever you are. The Smartwares Smart Smoke Detector ensures you are always aware and can react quickly if a fire starts. The Detectors are easy to install, and will emit a loud sound signal, and send a notification to your smartphone or tablet if connected to the Smartwares Pro Link. Feel safer when away from home, knowing you’ll be notified should smoke be present.
The Smoke Detector Set contains two smart smoke detectors and the Smartwares Link Gateway. The Link connects your home network with the free HomeWizard Link App, sending notifications to your smartphone or tablet.
$140, would prefer pickup (Auckland, North Shore) because they'll be a bit of a hassle to post but can post at buyer's expense. Never used, got them before the Casa de Cowboy redo and now we've got wired sensors so don't need the wireless ones.