SE Electronic Stepless Speed Controller Replaceable 15 amp fuse. The Safest Controller with 1800W Max Power and Fuse & Thicker 6ft Long Power Cord in Market! It can adjust your fan to full speed in summer and to low or medium speed in winter to ventilate your grow room according different need. If used with fan and filter for ventilation, the suitable and adjustable fan speed is good for utilizing your carbon filter more efficiently. Fuse Protected. UL listed for safe use. 15 amp maximum. 120 volt One control switch for 3 settings: Variable Speed, OFF, and Full Speed. Speed control dial to control variable speed: Low, Medium or High speed.