I have been using the synthetic urine kit for years flawlessly. The brand I use is "#1", Make sure the hand warmer is on the ace bandage side, and the other side is directly against your flesh (not a bunch of hair as this is insulation), I sit in the parking lot until it reaches 100 f (built in temp strip), at this point I go in and pretend I do not have to piss. Sit in the lobby for 20-30min drinking water (until i really have to piss bad). Then I tell them I gotta go now "bad", I go in the stall, immediately fill up the piss cup (only to the line), then actually piss in the toilet, if my piss is clear and it doesn't change the color of the water in the bowl I will pour what is left in the synthetic piss pouch into the toilet to match the cover. Zip up and done. I work in construction and can change companies quite often, I've probably used it 5-6 times in the last 7 years. Has never failed me. Same routine everytime.