Test gas in reusable cylinder "Ecomini" with 2.2 vol% methane (CH4) in synthetic air. Approx. 0.85 litre cylinder size at approx. 37 bar Volume: 31.5 litres Please return the empty cylinders to Esders GmbH after use. We will refill them. As a thank you for your contribution to environmental protection, you will receive a free pack of 100 Esders Connect measurements.