Basement Watchdog Standby Batteries are uniquely constructed with heavy duty plates to store more energy, provide longer run times and last longer in standby operation. The high reserve capacity can run compatible Basement Watchdog battery backup sump pump systems intermittently for days. They are shipped dry and vacuumed sealed to retain freshness. Activation is easily started by adding the 6 Qt. battery fluid pack (sold separately). Basement Watchdog Standby Batteries will accommodate the fluid sensor that will allow the battery backup controller to sound an alarm when distilled water is needed. This battery is not recommended for use with the Basement Watchdog BW12-120C, BW4000, CITS-50 or BWSP.