This two speed fan (extremely quiet at low speed) has an effective neutralization field of 2 ft x 4 ft. Discharge from 1000V to 100V in <1 sec. at 1 ft. No adjustment or calibration is required to maintain ion balance. Measures only 6" W x 7.4" H x 3" D, weighs 2.5 lbs. Operates on 120VAC with 6 ft. cord.