The CI-1050 Series of 100 LPM airborne particle counters are engineered with only the highest quality materials. We have built our reputation by providing highly accurate instruments that stand the test of time. An internal study conducted in 2014 confirms that particle counters returned for calibration over the past two years have an “In Tolerance” calibration rate of ninety-eight (98) percent! This study also included some units manufactured over 20 years ago.