In 2019, HTek Instrument was merged with ESI. ESI (Efficiency Scientific Instrument Co. Ltd) was founded in 2010 to produce the high voltage x-ray power supply. From 2012, ESI started to develop and manufacture the X-ray tubes and DPP(Digital Pulse Processor) Today, with combined technological experience and advantages accumulated in both companies over the past years, ESI is a worldwide market producer of advanced x-ray fluorescence system for complete solutions in elemental analysis with thousands of machines installed and operative all over the world. Every year high percentage of its revenue is invested in R&D with the aim to improve the analysis performance ESI is a SIP(Suzhou industry park, China) based company specialized in XRF(x-ray fluorescence) instrument for non-destructive material analysis, coating thickness measurement and material testing. Our mission is to provide the rugged user friendly XRF analytical system to meet with the most difficult element analytical needs.