They are very accurate. You recon the hcg, draw some up in a syringe and shoot some in the hole provided on the plastic wand thing. You have to make sure u put enough product in there as the liquid has to run out through that channel, Ill guess 1/10 of a cc. Well if its negative why would u even want to take a chance with it. I bought some from a reputable source on here a while back and it tested negative. The source gladly sent me different replacement after stating that " you can still use it for dieting". Because that source takes a long time to deliver I bought some domestically and it tested positive AND brought my boys home just fine LOL. I don't know bro, what price do you put on your two dear friends? At my age it doesn't really matter much but if you're a young un and you got plans for them boys dont fuck around with them, no pun intended !