If you want a meter for mining, on board ships, trips to completely inaccessible areas with extreme environments, then the options are probably the Fluke 28IIEX, Amprobe HD160, and maybe a Brymen. Brymen does not make intrinsically safe meters, nor are they IP rated so their suitability in extreme environments are not guaranteed. They are not suitable for mining operations where intrinsically safe ratings are needed. They are very well sealed and protected from environmental contamination though.