After rubbing the surfaces, redness indicates the detection of lead. Yellow means that no lead has been detected Lead swabs allow instant on most metal ceramic surfaces including toys, woodworking, dishes, jewellery, bath glazes, ceramics, plumbing, etc Safe and : Swabs and packaging are made of safe materials and are harmless to the human body. Please do not put swabs in your mouth Dip the swabs lightly but not completely, in water. After the swabs have turned a yellow colour, rub the surfaces with lead-containing splashes of colour Lead swabs are very sensitive, test result is achieved in less than 30 seconds, Manufacturer: hogtnd