Extension cable for S4K2U48BAT. cULus, CE, federal communications commission. Hardwire capability for permanent installation. Small 2U height maximizes available space. Rack-mount or stand-alone tower mounting. Input and output noise suppression. Higher output power factor of 0.9. PWM inverter reduces output voltage distortion Hot swappable user replaceable battery (integral sealed non-spillable). Add on batteries for extended back-ups. Automatic restart. Automatic and manual battery test. Units are field configurable with a PC as a frequency converter (bypass will be disabled).