【Solid Brass Material】These challenge coin blanks are crafted from durable brass, offering a sturdy and reliable material for your custom creations. solid brass and non electroplated brushed.on the surface.There may be trace on the surface because of non-electroplated brushed.Noted: The surface of the coins is coated with a protectived coating to prevent oxidation.Removing this coating before engraving can lead to better results. 【Perfect Size and Thickness】 With a diameter of 40mm and a thickness of 3mm, these coin blanks offer ample space for your DIY designs while maintaining a comfortable and manageable size. 【Full Flat Surface Design】 Each coin blank features a completely flat surface, making them ideal for precision laser engraving. This design ensures your intricate patterns and designs come out clean and clear.You can engrave various patterns or words,names on it. It can be used as hooks, rings, to make beautiful badge, charms, pendant, dangles, necklaces, custom key chain like pet ID tags, keepsakes,ect. 【Warming Gift】The engraving blanks would be great gift for DIY lovers. And it’s also a meaningful gift after engraving for be a friends, family, girlfriend, boyfriend, colleague, coworker, neighbor, classmate, father, groom, friend as meaningful gifts. 【Acrylic Box protection】Each set comes with an acrylic protection box to keep your coin blanks safe from dust and scratches. This ensures that your coins remain in pristine condition until you're ready to work on them. 10 Pieces Blank Challenge Coin Brass Laser Engraving Blanks 40mm Diameter Full Flat Surface Coin Blanks with Acrylic Protection Box Pattern for DIY Crafts Engraving(Thickness 3mm)