The cones are externally graduated from the plug up to 1000mL: 0 to 1mL x 0.1mL; 1 to 10mL x 0.5 mL; 10 to 40mL x 1 mL, 40 to 100mL x 2mL; with lines and numbers at 250, 500 and 1000mL. Each Imhoff Cone is manufactured from styrene-acrylonitrile and comes with a low-density polyethylene plug. To clean, simply remove the leak-resistant screw cap and plug. Reference: Standard Methods for the Examination of Water and Wastewater, 21st Edition (2005), Method 2540 F. 

Brand: DWK Life Sciences (Wheaton)