SinoTech company is especially professionalized in the field of optical instruments. For your choice , we provide many series of refractometers both of traditional and digital and a variety of gemological instruments such as gemological refractometer, spectroscope, polariscope, dichroscope, chelsea filter, gem magnifier , gem Gauge with favorable prices. Apart from that, we are also manufacturer of scientific instruments with high precision for your service, such as borescope PH meter polarimeter thermometer, to name only a few. You are most welcome to visit our website at Sinoptics Refractometer to find out more.