GASCO 34LS-301 Calibration Gas Multi Mixture, Carbon Monoxide 50 PPM, Methane 50% LEL, Balance Air contained in a 34 Liter Disposable Steel Cylinder, For Use with Any and All Gas Detectors, Cylinder Connection CGA 600, Calibration Certificate NIST, Made in the USA

Order 34LS-301, from Cal Gas Direct Incorporated, GASCO Calibration Gas is Made in the USA, Easy Ordering, Excellent Customer Service, Largest Selection in the USA