Jiangsu Wheatstone electric Technology Co., Ltd. the company now owns Tong Hui Wheatstone . WHEATSTONE petroleum testing instruments three brands. All the petroleum instruments manufactured by our company are in coincidence with the standards of ISO,ASTM,IP,GB,suitable to do determination of viscosity, water content, distillation, carbon residue, cloud point, solidifying point, foam, emulsification, flash point... [detailed]