Combine the quality calibration gas you need and environmentally-friendly waste reduction with the Gasco 4 Gas Calibration Gas Refillable Cylinder 58ES-409. This reactive, multiple gas mixture contains carbon monoxide, methane, hydrogen sulfide, and oxygen. Nitrogen is the balance,
The ES in 58ES stands for Ecosmart. Once depleted, you can return this 58 L, aluminum, Ecosmart refillable gas cylinder to Gasco for free. They even provide the shipping. There’s no need to keep an empty calibration gas cylinder around.