This accessory is a replacement for the 12/18-volt adapter cable with external speaker that came with your StreetPilot 2720. It allows you to power your unit off the vehicle's battery and hear the voice prompts. So if you need a new one, don't delay. You'll be lost without it.
WARNING: This product can expose you to chemicals which are known to the State of California to cause cancer, birth defects or other reproductive harm. For more information go to P65Warnings.ca.gov.