Nady CX-22SW One Space 2-Way Stereo, Plus Subwoofer Crossover Single rack space (1U)Shielded internal power supply with AC voltage select switch (~115V/60Hz or ~230V/50Hz) Shielded internal power supply with AC voltage select switch (~115V/60Hz or ~230V/50Hz) Phase inversion switches Low-cut subsonic filters for low frequency driverprotection Servo-balanced XLR inputs