Was going to fit to my Focus but have since sold it. GESI Emissions Systems is a leading emissions technology company based in Canada. The CAT basically tuens your car into an emissions free vehicle using reductive and oxidative creactions and special coatings. Stainless steel.
NO2 is reduced 98.7%, CO by 99% and HC by 95.8%
Read more here
https://www.gesi.us/guide/vehicle