This kit includes everything you need to easily get started, including 1 Total Reader, 5 Smart Sensors (used for relative humidity testing), and 2 Smart Logger ambient temperature and humidity recorders. - 5 ea. L6 Smart Sensors - 1 ea. Total Reader with Touch-n-Sense Technology - 2 Smart Logger Ambient Temperature and Humidity Recorders - 1 ea. Insertion Tool - 10 ea. Extensions - 5 ea. Protective Caps with Rubber Plugs and Butyl Gasket - 5 ea. Stainless Steel Covers - 1 ea. ¾” SDS Masonry Drill Bit - 1 ea. Wire Cleaning Brush - 1 ea. Vacuum Attachment - Certificate of Calibration - Floor Map - Instruction Manual - Carrying Case Rapid RH L6 sensors feature a customized version of the SHT35 humidity sensor from Sensirion that has a +/-2% accuracy tolerance at 50% and 90% relative humidity (RH). This important aspect of the L6 concrete RH testing system puts it in direct compliance with ASTM F2170. Standard SHT35 humidity sensors, found in other concrete RH test systems, start to deviate from the +/-2% tolerance at RH levels as low as 50%.