is the -4 an bigger or is the -6 an bigger sorry if posted in wrong forum....and how do you know from looking on the nitrous line i have a zex so i was wondering how you identify it?need to know befor i buy the nut size for bottle....

 

-6 is noticeably bigger

 

btw your zex is -4, I'v had all three kits zex, nx ,nos