I purchased a D5-300C model. This is a truly excellent piece of kit for providing extra HDD storage. I admit I was a little sceptical as to its operation and ease of setup but I needn't have been. It does exactly what it claims - when in operation you will see the additional hard drives appearing in Windows Explorer (I am using it on a PC running Windows 10) just like the internal hard disks inside your PC. I was impressed by the sturdy construction of the unit; true, the drive trays are plastic but they are quite solid and easily slot into the unit. TerraMaster provides you with all the accessories and tools you will need - fixing screws in two different sizes (one type for 2.5 cm and another for 3.5 cm HDDs), and enough of them for a full set of five drives, two screwdrivers (one for the fixing screws & one for setting RAID configuration), a reset tool, extra rubber feet and labels for the drive trays. You can also purchase additional drive trays and fixing screws - so you can have HDDs outside of the unit ready to slot into a vacant bay. Useful if you want to archive HDDs without having to remove them from the trays or if you want have spares ready for operation. I found the support team very helpful - they're available by email and reply promptly. I would certainly recommend this without reservation to anyone looking for additional hard drive storage.