The Yellow Box Portable oxygen analyzer is a transportable O2 measuring device in a rugged case that provides a versatile solution for high purity oxygen measurement applications. The Ntron Yellow Box is a compact, robust, transportable oxygen analyser that can be supplied with two or three zirconia sensors offering a fast response time and long service life with virtually no drift. Measurement ranges available are 0 to 1,000ppm, 0 to 25% & 0 to 96% O2 with a mA output per channel.