Well, I tried these since the drugstore home testing packages. that I first used. I tested positive on CBD products got clean or tested negative then tried “THC Free” CBD’s and tested positive again. I used these low cost strips and a drugstore kit both tested positive and then negative after 12 days with both types of testing. CAUTION if you use CBD anything and are positive DOT or other Federally managed anything you’re going to be in hot water! Test! Test!