Swarovski innovations colour Spring/Summer 2019 - The SWAROVSKI Elements Hot Fix Flat Backs have the glue already inside the back of the stone. The best way to apply these Hotfix is by using the Professional Touch Applicator. The tool will pick-up the round rhinestones, heat them until the glue begins to melt and then attach them to your fabric. It is quick, clean and very easy. You can also apply them using an iron.