They're all created about equal. Best thing to do is buy them online now and they will cost you $1.25 -$2.00 plus shipping that way you can test a couple or several times to get a good gauge. When stored properly and in date they are about 96-99% accurate. Test the first urine void of the day but don't use the first void for the real test. There's a bunch of companies that market them but some are actually made by the same company.