The manufacturer describes it as -

The Freedom Antenna® is the world’s first portable personal antenna with broadband capability to provide clearer reception for cellular phones and other wireless devices by extending the range and reducing dropped calls. Utilizing patented technology, the Freedom Antenna® is compatible with all major wireless carriers and technologies by increasing performance of mobile products in the frequency ranges of 800 MHz to 2.5 GHz. Designed in a convenient slim package for both fixed and mobile hands-free use in vehicles, offices, homes and is ideal for travel. The Freedom Antenna® is essential for sales people & executives, remote workers, or anyone frustrated by dropped calls and poor reception.

• Perfect for Cell Phones, AirCards, PDAs, Laptops
• For Home, Work, Travel
• Decrease Dropped Calls
• Reduces Dead Spots
• Enhanced Voice Clarity
• Works with all Major Wireless Carriers

We found the antenna does provide a boost to both our cellular and wifi signals.  As car kits have become extinct though, many manufacturers have stopped putting antenna ports on their phones.  While you can attach the Arc Freedom to a passive cradle, the boost this way is significantly less than using a direct connect cable.  Find the ARC Freedom antenna and other cell phone accessories here.

 Features include -

• Integrated speaker and control box
• Visor Microphone
• Handset Cradle
• PTT Remote Control Button
• Palm Microphone (optional)
• Full Duplex
• External Antenna Connection

If you have a Nextel phone and need a good in car solution, these kits are a great option.