Naturally Klean 1 - Hour capsules. I used them this week just as a precaution. You drink 5 glasses of water and take 24 pills over a 1 hour span before your test. So basically you are diluting but the pills keep your urine yellow and dense enough to pass the specific gravity test. I have had 4 or 5 people tell me they worked for them and they had smoked days before the test.