Secchi Disc, divided, black and white

A disc with a diameter of 250 mm for determining the  depth  of  visibility  and  light  permeability  of  water.  This sturdy  version  is  made  of  strong,  hard-wearing  plastic  and  has  a  lead  weight (diameter 5 cm, h = 2.8 cm) for  better  lowering. The approx. 15 cm high rod is fitted with an eyelet for fastening the lowering engine. The lowering line marked at intervals of 50 cm for better reading of the depth of visibility while the disk is being lowered can be purchased separately.

This version of Secchi disk is divided into four segments, two of them are black, and two are white.