DS Series DC Server Fans Wakefield-Vette DS Series DC Server Fans feature a two-ball bearing system, 10MΩ insulation resistance at 500VDC, and a -10°C to +70°C operating temperature range. These fans are available in dimensions from 40mm x 28mm to 120mm x 38mm and come with a 12V voltage rating. The advantage of the two-ball bearing system is that due to the small point load of the balls, less power is required to start rotation as they have less stiction than other bearing systems. Wakefield-Vette DS Series DC Server Fans provide ultra-high airflow and are designed for high-density applications.