I found taking the readings confusing. It would be much better if there were no control or test lines and just a positive or negative reading. I have been a victim of my neighbours drug use for 28 months which has caused horrendous Anaphylactic type symptoms and I needed definitive evidence that their drug fumes were in my system. It looked like a positive reading for heroine and cocaine but there was an extremely faint line beneath the top thick red line. I do not think I can use this as evidence for the Police even though their retched fumes continue to causing burning ear, nose, throat and oesophagus, respiratory distress, sinus inflammation and sinus headache, drowsiness, tingling lips and tongue with soreness of the tongue, extreme nausea, tickly cough, pain in the throat, even ear ache and head pain. This is why I needed more expert evidence.