Need to determine how clear the water is? Seeing may not be believing! Measure the turbidity or degree of visibility of the water you’re testing with our secchi disk. Many things have changed in the past 70 years - but not the Wildco® secchi disk! We’ve used the same white acrylic in its manufacture since our founding in 1938. Confidently compare your results with data from earlier decades! Specifications: * 200 mm (7-7/8”) diameter acrylic with stainless steel bolt * Two white, two black quadrants * Weights and instructions included * Sounding line kits include limnological secchis.