... Specification:Dual purpose for refractive index and reflectivity,Digital displayOilless test: don’t need the refractive lndex liquid Wide testing ... display,place scale sample(1.487)on test platform,then press test button 3.Press TEST BUTTON until the “04”appears,switch to ... display, place scale sample(1.755)on test platform, then press test button. 5.Press TEST BUTTON until the”04”appears,return normal ...