Since power failure at a pump station generally means a loss of the alarm features, there is a requirement for a 'Battery Backed Up' Level Alarm. All features of the standard and deluxe models are common to this device however the unique feature of this product, is the provision of battery backup. Continuously charged by mains 240VAC power supply, the unit's battery has sufficient capacity to drive the audible alarm for a period of 5 minutes and the visual alarm for a period of 12 hours after power failure has occured. The battery is rated for continuous charging.