5.25' Bay size backplane for 4 x NVMe HDD/SSD Metal frame with stainless HDD carriers Worry-free sliding-in carrier design for easy installation and swapping of drives 1 x 5.25' bay backplane for 4 x 2.5' NVMe HDD(SSD) U.2 solution 2 x 15pin power connector + 4 x Mini SAS HD (SFF-8643) Supports U.2 Gen3 32Gbps (full performance) and Gen4 64Gbps performance Vibration reducing springs on each HDD tray 2 x 4020 cooling fans for super cooling & fast heat sink LED Indication: Power On: Solid green, Orange blinking:Accessing With super 4020 fan x 2 for best air ventilation