The enclosure supports 3.5-inch and 2.5-inch SATA hard drives with SATA III (6G) interface and USB-C 3.2 Gen 1 connection. There is no specific manufacturer information on the maximum supported capacity, but SATA interfaces and modern enclosures are generally compatible with very large hard drives, including 20 TB models, provided they fulfil the SATA standard. As the enclosure is designed for 3.5-inch SATA hard drives and offers a power supply via an external power supply unit, it should also be technically capable of operating 20 TB hard drives. Axagon does not specify an official capacity limit. To summarise: Yes, the enclosure can very probably also handle 20 TB hard drives as long as they are SATA 3.5" models.