I purchased two of the Icy Dock adapter to fill the fill the four 5.25 slots in an iStar server case. They are not tray-less, but work well in my server and I won't be pulling them out unless the HDD fails. Trays actually provide a better drive connection to the back-plate. The end result was 6 2tb drives (total 12 tb) in a 4u server case, that can be services from the front without pulling out the server. The iStar case I have has 3 more 5.25 slots and I am contemplation purchasing a 4x3.5 for 3x5.25 Icy dock when I need expansion. The fan on the unit produce average noise levels. For a server that is in another room that's fine, but if you were to use them in a home theater pc (HTPC), I would change them out to a silent fan. The fan is mounted behind the units and are easily remove and have a 3 pin connector. The back-plate has 2 sata power connectors and 3 sata drive connectors, one for each drive. The are really direct connect drive and the unit raid or pooling or multi drive over a single sata connection. So, if you add one of these you need 2 power connectors and 3 sata cables. Icy Dock built a quality product the works well.
