360pcs size ss20 (4.7mm) Aqua Bohemica Preciosa MC 12-facet Iron-on ChatonRoses (HotFix Flatbacks) Preciosa Czech Genuine Crystals, 12-facet Machine Cut Chaton Rose Iron-on (Flat Back Hot Fix) stone size ss20 (4.7 mm, 0.18 inch), Aqua Bohemica color Silver Foiled 360 pcs in a package (PE bag) Hotfix stones feature a special low-melting-point adhesive on the bottom of each stone. This glue is activated by heat at temperatures between 120C-170C (248F-338F) and bonds with the carrier material. The glue hardens as it cools and the stones are securely and permanently fixed. Crystals and Beads for Friends offers free shipping for orders over $25.