HJS is an old German brand of three-way catalytic upgrade. HJS was founded in 1976 and officially started the r&d and manufacturing project of three-way catalytic converters in 1985. HJS has always put environmental protection first, focusing on catalytic and emission reduction technologies for passenger vehicles, commercial vehicles and some non-road emission projects. The emission of harmful substances of cars is reduced through the continuous innovation of environmental protection technology so as to achieve the goal of protecting the environment and saving resources. Almost all retrofit exhaust uses HJS competitive three-way catalytic converters.