I'm not sure what everyone is talking about when saying you have to beat the $hit out out of the chamber, heat up the tank, or change the tank when putting a sj mod chamber into a fx1. Unless I got really lucky and got one of the last new fx1 chambers ever made I'd have to say i dont know what everyone is talking about, lol. This chamber is a brand new sj mod chamber and fits better in my fx1 than the last mod chamber I had in my old SN.