The Grant Mag One DUO is a universal magnetic filter that is designed to give system protection and it can be installed as part of a new heating system installation or it can be retrofitted to an existing installation. Compatible with both traditional fossil fuel boilers as well as air source heat pumps, the Mag One DUO provides innovative protection, protecting system components from damage and consequently it can increase the performance of your heating system. Whether you are having a new Grant Vortex oil boiler installed or fitting an Aerona heat pump or you need a new magnetic filter for your existing heating system, the Mag One DUO filter can provide the protection you need.