Home / Mains Conditioners & Blocks / Fidelity Audio Passive Mains Filters Fidelity Audio Passive Mains Filters Sort By Sort by:Most popularWhat's newPrice low to highPrice high to lowName A to ZName Z to A Showing products 1 to 2 of 2 Sort by:Most popularWhat's newPrice low to highPrice high to lowName A to ZName Z to A Fidelity Audio NN Ultra X MK2 Mains Purifier £379.00 £315.83 (ex. VAT) Fidelity Audio NNU X Reference High Frequency Mains Purifier £599.00 £499.17 (ex. VAT)