GX PRO Pet Dog and Cat Refractometer with ATC Blood Protein Serum Measuring Range : Total Serum Protein: 2-4g/dl / Refractive Index: 1.000-1.060RI Dog &lt;br&gt;1.000-1.060RI Cat Minimum Division: Total Serum Protein : 0.2g/dl / Refractive Index : 0.001RI Dog / Refractive Index : 0.001RI Cat Accuracy: Total Serum Protein : 0.2g/dl / Refractive Index : 0.001RI Dog / Refractive Index : 0.001RI Cat Automatic Temperature Compensation (ATC) Triple scale reads the Total Serum Protein (SP) and refractive Index (RI) of dogs and cats.