Voltcraft dt 8820 4 in 1 multifunctional environmental measuring instrument voltcraft dt 8820 the voltcraft dt8820 multifunction environmental measuring instrument measures light intensity temperature sound levels and humidity it has a max hold function and auto power off to save battery life supplied with a detachable microphone windbreaker an illuminance sensor attachable k type immersion probe 9v battery nylon carrying case and an operating manual voltcraft dt 8820 multifunction