Experience the reliability and efficiency of the Sentinel X400 Central Heating System Restorer, a 1L solution designed to tackle circulation problems and sludge build-up in your boiler. Specifically formulated for hydronic systems, this product is ideal for maintaining the optimum performance of your boiler and ensuring warm radiators throughout your home. Crafted in the United Kingdom, the Sentinel X400 is compatible with a range of boiler types and is recognised for its corrosion-resistant properties. The silver-coloured storage tank water heater boasts an energy efficiency rating of A, promoting both sustainability and cost-effectiveness. Keep your heating running smoothly with this premium system restorer. brand new 4 pack