These adorable resin earrings are made with high quality UV glow powder. In order to glow, they need to be charged in either direct sunlight or a UV lamp. The stronger the light and the longer they charge, the better and longer they will glow. Each cat head measures approximately .6 cm high x .8 cm wide x .5 cm thick Earring posts are hypoallergenic stainless steel with butterfly earring backs. Earrings come in a white cardboard marble gift box with a keychain UV light, making them perfect for gift giving.