4TH OF JULY PROMOTION! The Product Preservers Anti-Scale System protects your tankless water heater from damage due to scale formation. This system does not add chemicals to the water or require electricity. As water flows through the filter, hard water minerals form inactive scale crystals which flow through the water heater without sticking to the heat exchanger. The system virtually maintenance free as the filter only needs to be changed every two years. Replacing the filter is easier, faster, and needs to be less frequently than using isolation valves to flush a water heater with a cleaning solution to remove scale buildup. 3/4” NPT in/outlet connections, 25-1/4” tall, 5-1/2” diameter