Test gas 4-Gas Sewerin Mix in reusable bottle ‘Ecomini’ with 2.2 vol% methane (CH4) 40 ppm carbon monoxide (CO) 2.0 vol% carbon dioxide (CO2) 17.5 vol% oxygen (O2) in nitrogen (N2). approx. 0.85 litre bottle size at approx. 37 bar Contents: 31.5 litres Please return the empty bottles to Esders GmbH after use. We will prepare and refill them. As a thank you for your contribution to protecting the environment, you will receive a free package of 100 Esders Connect measurements.