Mufan CO2 Regulator + Solenoid Valve W21.8 UK Aquarium - Fits Fire Extinguishers. W21.8 connection (UK standard). 1 x Mufan CO2 Regulator with dual gauges (W21.8 connection). This regulator is designed to work with both dedicated aquarium CO2 systems and standard UK CO2 fire extinguishers.
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