The Rugged Oil/Water Interface Meter accurately measures the thickness of floating hydrocarbon product layers (LNAPL) and sinking layers (DNAPL) as thin as 1 mm (1/200 ft). When properly grounded, the meter is intrinsically safe for explosive or hazardous environments like oil refineries, remediation sites, and landfills. The tape is ASME-certified and made of high-tensile steel, with a Kynar coating to protect it from hydrocarbons, solvents, and other harsh chemicals. Certified to UL and CSA standards. Class 9098-01 for hazardous locations. Class 9098-81 (U.S.A.) for hazardous sites. Class I groups A, B, C, and D.