the overdose stopper is the first drug detector that can be built into any syringe. the system can test for any contaminant in a syringe, like fentanyl or carfentanil. when users draw a lethal dose into their syringe, a patch on the syringe changes color to tell the user whether their drug is contaminated. the overdose stopper was designed and developed as a potentially life-saving measure for users, so they can know what’s in their dose and get a second chance at life. the system encourages users to “look before you shoot” — a moment’s pause that can potentially save thousands from overdosing.