The GRAYL Ultrapress Cartridge Replacement is a replacement purifier cartridge for the UltraPress bottle. These cartridges last up to 300 cycles, or 40 gallons, so when you've reached the limit with the old one, switch it out with a new one. How can you tell? Easy, at the end of its lifespan, press time increases. When it starts to take 25-30 seconds to press, it's time has come.