Kensington, a well known accessory design and manufacturing company. has released an iPhone 4 system that will let you know when you get separated from your iPhone. Never again will you have to worry about leaving your phone somewhere or having it fall out of your holster or purse.

BungeeAir Power Wireless Security Tether and Battery by Kensington consists of a protective case, a free app from the App Store and a small wireless security fob that has an attached key ring.  The case and fob maintain a wireless connection; when your phone and the fob are separated, an alert goes off on the fob and the iPhone automatically locks.

The system has some other features as well, such as a way to locate either your fob or your phone. You can press a button on the fob and your phone will sound an alarm, or you can use the find my key function within the app on the iPhone. There are other customizable features, such as setting the distance before the alarm goes off.

The case has a built in battery that claims to add four hours of talk time to your iPhone. The case also incorporates a stand for using your iPhone in landscape mode. Kensington is releasing another model that does not have the power case called BungeeAir Protect Wireless Security Tether. This system will cost $20 less.

Kensington is selling the BungeeAir Power Wireless Security Tether and Battery on Amazon exclusively until October 5, 2011. It costs $99.99.