Replacement purifier cartridges for the UltraPress® are designed to last up to 300 cycles (40 gal. / 150L). Lifespan will decline when filtering and purifying water with high levels of silt, sediment or tannins. Cartridge press time increases towards the end of the cartridge lifespan; when press time reaches 25-30 seconds, the cartridge should be replaced. Cartridge continues to protect, even as press time increases. Compatible with One-Way Silicone Valve for electrolytes and drink-mixes. UltraPress cartridge and one-way valve ships pre-installed in every UltraPress Bottle.