High Power Factor; Class A Sound Rating; MB2x30 also operates F30SS; MB1x40 also operates F40, FB40, FB40SSF40T10, F30 or F30SS; MB2x40 also operates F40, FB40SS or F40T10; MB1x40/120RES is Normal Power Factor and operates only F40T12, FC12T9 or FC16T9.