Healgen Scientific Harm Reduction Surface & Residue Drug Test Kit, Cassette Format, 2 Panel, FEN Fentanyl, XYL Xylazine, 20/Box Harm Reduction Drug Test Cassette for Residue, Surface, Pills, 2 Panel, 20/Box The Fentanyl/Xylazine MSRP: Was: Now: $39.75 Options