Fluorescent samples are vibrant and glow under a black light. This filament is a bit translucent, so the patterned infill shows through the surface. Each Sample charm is 42mm wide and double-sided. The default attachment paired with this charm is a matte black keyring keychain. Keyring keychains are available in Matte Black, Gunmetal, and Gold, while Lobster Claw Charm Attachments are available in Matte Black and Silver. Please send us a message if you would like a different charm attachment with your Sample.