IBM System Storage DS4000 EXP810 Expansion Unit. Number of expansion bays total (free): 16 (16). Operating relative humidity range: 8 - 80 %, Operating temperature range (T-T): 10 - 35 °C. Dimensions (WxDxH): 483 x 559 x 132 mm. Power requirements: 100 - 240V, 50/60Hz