Compact Fans (AC): Hicool manufactures these AC & DC Cooling Fans in varying voltages of 12V DC, 24V DC, 48V DC, 115VAC, 230VAC & 415VAC. AC cooling fans are available in frequencies of 50 Hz and 60Hz. These fans are available in both plastic blade as well as metal blade. The sizes of compact fans vary from 50 mm to 280 mm. All fan models are available in both ball bearing as well as sleeve bearing. DC Compact Fans have special features like Fan Failure Alarm and Alarm Signal for speed monitoring.