After rubbing the surfaces, redness / purpled / mean the detection of lead Yellow mean not lead is detected Lightly dip the swabs into the water, not completely, after the swabs reach yellow color, use lead paint swabs to rub the surfaces Lead swabs is very sensitive, result achieve in less than 30s Lead swabs provide immediate on most metal ceramics surfaces Including toy, woodworking, dishes, jewelry, bathtub glazes, ceramics, plumbing Safe and green: swabs and package make from safe materials and not harmful to the human body Please do not put a swabs in your mouth, Manufacturer: jklymm