The research team will assess the acceptability and feasibility of "take home rapid drug tests" to test for fentanyl exposure among 100 participants from the target population. After the enrollment and baseline survey, participants will be provided with rapid drug tests that detect the presence or absence of fentanyl in their drug supply. Half the participants will be asked to test their urine to see if they have been exposed to a fentanyl-contaminated drug. The other half will be asked to test the residue of the drug that they intend to use. Study participants will then be asked to return in 2 weeks for a brief follow-up survey that will assess whether they used the self-tests, whether the technology was acceptable and easy to use, and whether and how a positive test result altered their drug-using and overdose prevention behaviors.