Say goodbye to single use coffee filters. The GSI outdoors Reusable Java Filter #4 is designed to brew coffee or tea over and over. Easy to use and clean. Durable Nylon. Designed to fit into traditional #4 cone pour over coffee makers. Reusable filter fits and stores away easily when not in use To use, place the reusable # 4 filter in the Collapsible Java Drip or other #4 drip coffee makers. Fill with coarse-ground coffee or tea leaves, pour boiling water through.