Give your GeoPress® a boost! In April of 2023, we redesigned our Cartridges to accommodate a One-Way Valve. It's a significant upgrade that includes a new "core" plus "flow channels" making it possible to add electrolytes and drink mixes into a GeoPress for fast, healthy hydration when on-the-go. Note: the GeoPress® One-Way Valve now ships pre-installed in every GeoPress.