Metal frame with stainless HDD carriers. Worry free slide-in carrier design, just slide in the tray. 1 x 5.25″ bay backplane for 4 x 2.5″ NVMe HDD(SSD) U.2/U.3 solution. 2 x 15 pin power connector + 4 x SlimSAS connector. For 4 x 2.5″ U.2 NVMe HDD/SSD. (PCIe 3.0/4.0) 4 individual carrier for swapping in/out. Super cooling 4020 fan x 2 for best air ventilation. Security metal keylock. Support U.2 Gen3 32Gbps (full performance) and Gen4 64Gbps (performance may vary depending on environment). Vibration reducing springs on each HDD tray. Dimension: 159(L) x 145.8(W) x 41.6mm(H). Weight: 0.62 kgs.