Sony Xperia XZ Dual 32GB [CARRIER?]. F8331 Android Smartphone Tested. Model Number: F8331. This Xperia XZ Dual system is equipped with 32GB of storage and runs Android 8.0. Storage Capacity: 32GB. This device has been tested with Independent 3rd Party Testing Software, and its erasure status, lock status, and functional test results are reported below.