Available exclusively as Smart Refills through the Mitte app: pack of four Mitte CO₂ Cylinders filled with 425g premium food-grade carbon dioxide, bottled and sealed in Germany. Smart Refills are order reminders, guaranteeing you’ll receive replacement CO₂ cylinders before your current ones run out. Opt-in directly in the Mitte app. Safety instructions: Contains pressurized gas. May explode if heated. Keep out of direct sunlight. Store bottle(s) in an adequately ventilated and dark place. Keep away from children.