conductivity tester, handheld device provides a qualitative visual indicator of the conductivity of different solutions, acids or salts, Two brass probes can be touched to a solid substance, or immersed in a liquid, to show conductivity on green LEDs
Ratiometric Turbidity Meter, Infrared (LED) Lamp, Material: Plastic, 2020i version best suited for natural waters, samples of higher turbidity and samples with some color
Ratiometric Turbidity Meter, Infrared (LED) Lamp, Material: Plastic, 2020T version with tungsten bulb is best suited for low level drinking water applications