Purchase this item and get 
Refillable storage cylinder with 500g CO2.
Key Features:
- CO2 storage cylinder for all CO2 systems. Supplies aquarium plants with their main nutrient carbon dioxide (CO2) while preventing algae
- TΓV-tested, refillable 500g CO2 reusable cylinder (thread W 21.8 x 1/14). With pressure relief valve for safety
- Does not stand on its own. Requires a stand (JBL PROFLORA CO2 CYLINDER STAND) or a wall mount (JBL PROFLORA CO2 CYLINDER WALLMOUNT)
- Because CO2 liquefies under pressure CO2 pressurised gas cylinders must be in an upright position when in operation
- Package contents: refillable cylinder, ready-filled with 500 g CO2, dimensions: 43 x 11 cm, thread W 21.8 x 1/14
