Foren-Tests Lead Test Swabs and Copper Test Swabs are designed to provide the crime scene investigator with the ability to conduct a presumptive chemical field test for the presence of lead. Simply remove the protective cap, moisten the attached swab pad with the included distilled water, rub the swab on the suspected lead mark to transfer a sample of the mark to the pad, break the crush vials in the plastic tube, and observe a color change to indicate a positive presumptive reaction to the presence of lead or copper. Provided as a package of eight swabs.