Carefully center the fitting in the tool or your crimps will be kaddywampus and you'll have to do them over with a new fitting and hose. I hope this time the send me one that’s actually new, never used and not broken. I am following the MFG instructions to the tee, but am still having leaks. I have used it on two cars and have had leaks on both. Good to have if you are doing AC on an antique or hot rod build.