A friend of mine went to COSTCO looking for CP1500 UPS but could not find any on sale. Later he went online and found model CST150UC for $125 alter discount. However, this model states "Simulated Sine Wave". Never heard of such a thing. Anyway, can someone give me the Costco online model number of the CP UPS that seems to have no RFI? Tnx, Ray, N6VR/W7YA