Oil in Water Analyzers measure the concentration of mineral oil dispersed in water by reading ultraviolet absorption through the sample, giving a result in 5 seconds without lengthy solvent extraction. Dual photometer design covers 0 to 1000 ppm with precision within 5% of full scale, enough to confirm discharge limits before effluent leaves the site. Operation spans minus 20 to 40 degrees C and 10 to 90% humidity, and a 9 V supply drawing under 10 W suits field and shipboard use. Typical uses include produced water in oil and gas, refinery and power plant effluent, bilge water checks for MARPOL compliance, textile wastewater and spill response.