Unfortunately, I had to rate this product a 1, because there was no zero. I bought the gallon container of urine off, followed label directions and soaked the affected area of my carpet, plus a 6" area around it. I also lifted the carpet to both ensure it was totally saturated, and to soak the underpad and sub-floor as well. I let the area dry, and had the same odor problem as before I began. I still had enough to repeat the process, which I did a day later...again with ZERO reduction/removal of the urine odor. I can't believe I was duped by misleading advertising...and this junk was labeled "veterinarian strength". In order to get rid of the odor, I cut out the area of carpet (luckily it was a corner area of the family room), removed the padding as well, and scrubbed the now bare floor with a pine cleaner, and voila!...problem gone.
All this being said, my suggestion is not to waste your hard-earned money on this product. Do some research, as there are many other products out there, which, in hindsight, I should've considered using. Good luck!