I tryd frig 12 & 414b I have found some problems with frig 12 on the older systems and on systems not size right it will not pull down to temp has it will with r12 I know the size needs to right but its a hard sell all the custermer knows is it work just fine befor w/ frig 12 there is a diff. of coill temps from 414b .
r-414b has lower coil temp . what do you like to use 414b,mp66,frig12 what works for you and why the one I like is mp66 it looks close to r12 in low temp