External hard drive - USB-C 3.1 Gen 2, fast file transfers with speed up to 515MB/s, passport protection, 256-bit AES hardware encryption, WDBK3E2560PSL-WESN
Data Storage Device - USB 3.0 (backwards compatible with USB 2.0), WiFi, DLNA, UPnP, SD card slot, built-in battery with up to 10 hours battery life, WDBSMT0040BBK-EESN
External hard drive - 2.5", USB 3.1 Gen1 (backwards compatible with USB 3.0/2.0), water/dust/impact/pressure resistant, passed the MIL-STD-810G Method 516.6 transit drop test - fall resistant, weighs 181g