Size: diameters are 18mm(0.709in.), 20mm(0.787in.), 25mm(0.984in.) and 30mm(1.181in.) Color: Clear(transparent) Material: Rhinestone crystal glass, NOT PLASTIC OR ACRYLIC. Usage: Decoration for sofa/booth//headboard/KTV room or other DIY home creative decorations. About color difference: please allow 5% color difference, because of lights/camera/patchs and other factors, it could not avoid color difference. REMIND: When you receive and open the parcel box, please be carefully so as not to be scratched by the prongs. Please put the item where the children cannot get it. To protect and keep the good looking of the tacks, we suggest you to use rubber hammer for installation.