YangHong Special Power System Co.,Ltd., a professional manufacturer and distributor of power supplies and security testing instruments as AC variable-frequency power supply -110V/120V/220V/60Hz &100V/127V/230/240V/250V/50Hz and security insulation&tolerance voltage tester. Since its foundation, the company has been in the business of R & D and production of green power supply and hi-pot & insulation tester, and been providing customers with complete services of product testing solutio