Abstract: A device for gas analysis, which determines the content of two or more gases in a gas flow. The device includes at least one source for emission of two or more ray paths of radiation of a detectable wavelength, a cuvette device having an inlet and an outlet for uninterrupted gas flow, and a detector device for conversion of the radiation into an electrical signal. The source(s), cuvettes, and detectors are arranged such that ray paths emitted from the source pass through cuvettes containing gas and to detectors to permit analysis of two or more gases in a gas flow. In a preferred embodiment, the cuvette device includes a block having cuvettes positioned in each of the ray paths, which cuvettes are interconnected to form an unbroken conduit for gas flow from inlet to outlet.