Product Description Item Number | 10121217MSA Altair 4X & 5X Replacement CO/NO2 Sensor Replace & repair your MSA Atlair 4X or 5X Multi-Gas detector with MSA's replacement Xcell Carbon Monoxide & Nitrogen Dioxide sensor. Need some DIY help changing a sensor or just some friendly technical help with repairing your instrument? Call customer service @ 1-800-949-7233. Buy with confidence with quick shipping and free technical support! Gas: Nitrogen dioxide & Carbon MonoxidePackage: Two-toxRange: 0-50 ppm NO2, 0-1999 ppm COResolution: 0.1 ppm NO2, 1 ppm COResponse Time (typ): t(90) <15 secondsAlarm Setpoint: Min 1 ppm/ Max 47.5 ppmWarranty: 3 yearsAdvantages: • Long life: >4-year life means fewer sensor replacements over the instrument's life.• Response: industry-leading response time not only helps to save lives, but your time and money as well.• Stability: when it comes to helping to save lives, be secure in knowing that XCell Sensors are rock solid performers.