Is the bank 1 cat the one closer to the radiator or the one on the back side of the motor thats connected to the exhaust manifold? Mazda Millenia 2.5L v6 2001....Thanks for your help

 

closest to the firewall

 

thanks man, i have to replace that god forsaken peice...it costed me 509.99 for the part and gaskets. Its also throwing a po421 code and a egr code and radom misfire codes...a i wanted to make sure it was the cat so i took it to a shop and he tested my o2 sensors and my egr and he said he is positive that it is my cat. thanks man