Donaldson Blue coolant filters use Synteq media to remove fine contaminants from sensitive coolant systems. Donaldson Blue coolant filters with Additive Replenishment Technology also maintain cooling system balance through a controlled release of additives, which extends the coolant maintenance interval up to once a year or 150,000 miles / 195,000 km.Proven and proprietary Ultra-Web® technology delivers longer filter life, cleaner air and greater cost savings than other types of cartridge filter media. Made with an electrospinning process that produces a very fine, continuous, resilient fiber of 0.2-0.3 micron in diameter, Ultra-Web forms a permanent nanofiber web with very fine interfiber spaces that trap dust on the surface of the media.