Amazon offers the Kensington BungeeAir Wireless Security Tether and Battery for iPhone, model no. K39291US, for $51.24 with free shipping. That's $4 below our January mention and the lowest total price we could find now by $2. This iPhone security kit comes with a wireless security tether, battery, and case. When your phone and BungeeAir keyfob are separated, your phone will lock automatically and send an alert to your keyfob.