So I bought a catalytic converter to get me by until I can get a better one (need to get a new inspection sticker asap) and so there is no flow indicator on it. Emailed the person and they are saying it is a 3way so the air flows both ways. 3way cats have been used since the 80's but you still have cats that are uni-directional (just put a new cat on my RX-7 from magnaflow and it was unidirectional) so I don't know whether or not to believe them...

 

Since you provide no link or other info hard to tell what you are buying and or if it is a 3 way or not

 

Well the question wasn't if it was a 3-way but if a 3-way automatically means it is bi-directional...