... recalibration function allowed. (6)Have Bluetooth features to choose from.(7)Direct display of hardness scales HRB, HRC, HV, HB,HS, ... value,impact direction,material and hardness scale etc. Technical Parameters:Display: 12.5mm LCD with back lightMetric/ Imperial: conversionRelative humidity: ... ≤90%Conversion: HL-HRC-HRB-HB-HV-HSDAccuracy: Display error ±0.8% at LD=900Memory: 50 data can be ...