Synology RX415 Diskless System 4-Bay Expansion Unit increases capacity of 1U RackStation servers Port eSATA: 1 x eSATA II HDD Interface: 4 x SATA (4 x Bay) Form Factor: Rackmount Power: Power Recovery: Synchronized with the Synology RackStation Power Supply Unit / Adapter: 250W AC Input Power Voltage: 100V to 240V AC Power Frequency: 50/60 HZ, Single Phase Power Consumption: 48W (Access), 15W (HDD Hibernation) Temperature: 5°C - 35 °C Humidity: 5-95% R.H Dimensions: 1.73 x 16.95 x 11.42 (H x W x D) Weight: 9.33 lbs.