Sell original HORIBA LAQUAtwin Calibration solutions for Electrical Conductivity (EC) meters. Includes: 1 FULL 14 ml bottle at conducitivity of 1.41 mS/cm - model 514-22 1 FULL 14 ml bottle at conducitivity of 12.9 mS/cm - model 514-23 These are the original calibration standards included with the meters LAQUAtwin EC-11/22/33