KANDI CORP-Crystal Style HotFix Birthstone Embellishments: December. This set includes 3.5mm and 2.5mm hotfix Swarovski jewels in sweet lilac; rich Persian blue; and cool crystal clear. To attach these gorgeous gems to fabric; paper; wood; and even glass all you need is any hotfix tool (not included) or iron (not included) because the adhesive is already on the back. Imported.