Stablcal Standards Calibration Kit, for 2100AN, 2100AN IS, TL2350 and TL2360 IS Laboratory Turbidimeters. Stablcal Stabilized Formazin Turbidity Standards are true Formazin dilutions developed for use in any turbidimeter. Kit includes sealed vials of 0.1, 20, 200, 1000, 4000 NTU and 7500 NTU standard.