QF stands for Quick Fix 4.2. It's sold at head shops generally. It can be heated and reheated without harm...unlike human urine. It costs a little bit, but in these days and times, it's worth it if you are trying to save your job. Read and study the substitution method and PRACTICE at home today. Read others success stories for hiints and tricks to help. If you go with someone's clean pee then you will have about 8 hours of room temp to play with until the human urine will start to go bad. Just take today as a study and practice day and hopefully later you will start to feel confident in your method of choice. When you are practicing, use tap water in a 2oz travel size bottle. Otherwise for the real test, use QF or real clean urine. Good luck and keep us posted.