1.Suitable for mold steel,stainless steel,steel,aluminum 2.The hammer comparing with the product must be in the appropriate range of pounds 3.Keep a vertical angle between the product and working platform. recommend to use tools to fix the product.avoid injuring hands. 4.These stamp sets are lightly coated with oil. Simply wipe down with a dry paper towel or rag before using. (Avoid wiping with anything wet - water will cause stamps to rust.)