Garrett Battery Backup Module for Garrett MT 5500 Metal Detectors. The Battery Backup Module by Garrett allows for convenient 12V operation and operates up to 20 hours on one charge. The Garrett Battery Backup Module is available in the following models: 2225400: Garrett Battery Backup Module for Garrett PD 6500i Metal Detectors - 2225400 2225700: Garrett Battery Backup Module for Garrett CS 5000 and MS 3500 Metal Detectors - 2225700 2225770: Garrett Battery Backup Module for Garrett MT 5500 Metal Detectors - 2225770 For more quality Metal Detector Accessories by Garrett please visit our Garrett Metal Detector Accessories page.