The RapidPure^® 6.5" Replacement Purifier Cartridge lets you keep using your Trail Blazer gravity feed purifier for years to come. This water filter replacement element is easy to install and reduces your environmental impact by letting you reuse the same water purification system. More than a filter, RapidPure purifies water by removing over 99.99% of viruses, bacteria, parasites, sediment, and more. With no pumping, priming, batteries, or waiting, this fast water filter is the best water purifier for group camping, hiking, and backpacking, and works even after it has been frozen.