If you had a habit of missing phone or keys, and spent important time in checking pockets, bags and everywhere, then here's a solution: Motorola Keylink(Phone and Key Fineder).
According to Motorola,
Keylink is a small device that you attach to your keychain. Using the Motorola Connect app on your phone, you can connect your keys to your phone in case either tends to wander off. * If your phone decides to play hide and seek with you, you can press a button on Keylink to make it ring up to 100 feet away. Or if your keys get a similar idea, you can use the Motorola Connect App to make Keylink ring.
The great thing is Keylink is compatible with Android and iOS devices. Simply download the Motorola Connect app from the Google Play Store or the Apple App Store today to get started.
Keylink features: Never lose your Phone or Key again
Compatible: Motorola Keylink pairs with any Android or iOS smartphone using the Motorola Connect app.
Key/phone finder: Make your phone ring anywhere up to 100 feet away.* Or use the app to see where your keys are on a map.
Skip your password: Keeps your Motorola or Droid smartphone unlocked when your keys are nearby—no need to enter a password.
Splash-proof: Keylink can get a little wet
Battery that lasts: Full year of battery life using a replaceable standard coin cell battery
You can purchase one for $24.99 at Motorola.com and T-Mobile.
Source: Motorola Blog