max wdIts 20TB on each internal bay, maximum total of 40TB in RAID 0 confuration. Maximum size for external drives connected to each USB port is 4TB total of 8TB.batu gerinda poles merk WD 4 dunakan untuk pemolesan besi dan stainless steel IRON & STEEL GRINDING ukuran 100x6x16mm atau 41458 speed max 15.300