New replacement resin for Race Glaze refillable Maxi water filter. This is 0ppm resin, the same as the original filter is pre-filled with. Simply tip the old resin away when water produced starts to contain dissolved solids and add the entire contents of this bag. You can tell when the old filters resin is nearing the end of its life as water will start to leave light watermarks, or you can send a sample of your filtered water to Vertar for testing. This service is free. Note: our £5.95 shipping rate covers mainland UK, for offshore/Highlands/NI please contact us for supplements.