The Canvio Flex 4TB drive from Toshiba does perform as expected for a 4TB 2.5’’ drive, MQ04UBB400 relying less on caching versus the drives found with Silicon Power external drives, which usually use Western Digital internals. Unlike models from WD, the internal board of the drive does offer a Micro-B 3.0 connector directly and not SATA, so no daughterboards are required here and the overall length of the total assembly is shorter.