The earrings are made from recycled oak wood. Depending on the grain of the wood, they may vary slightly. All handmade earrings have stainless steel studs. A certificate of nickel release is available. Manufacturer: Sonja Ritschmann, Gartenstraße 32, 40764 Langenfeld, info@schmuckwald.de The earrings are treated with a natural oil-wax mixture to beautifully highlight the grain and protect the wood.