Anti-scale systems with proportional dosing. European made, 3 piece, transparent and blue housing, ports 3/4” BSP brass inserts and pressure relief. For the treatment of drinking water, in compliance with EU directive 98/83/CE. The Atlas Filtri proportional dosing system is equiped with a special suction device which makes use of the “venturi effect” dosing the main water flow with polyphosphate in accordance with the European regulation thus reducing scale. Maximum hardness is 500ppm. These kits are easily installed just in front of the boiler on the cold water inlet feed or at the mains for whole house protection. 15mm or 22mm versions available. This unit has significantly lower running costs as the internal dispenser is refillable allowing you to buy Polyphosphate refills that contain more dosing capacity than disposable refill cartridges.