Your link describes a product that sounds an alarm if the widget gets too far separated from your phone, ensuring that you don't leave it behind somewhere. This widget lasts about a week on a battery charge and requires a monitoring app to always run on your phone (thus it can't work with iOS).

The Hone only alarms on demand (it will find your keys, but won't automatically alarm when you leave your keys), does not require an always-on monitoring app, and will last about half a year on a single battery.