This coffee mug has a double-layer design with a 304 stainless steel liner for freshness and corrosion resistance. The outer layer is 201 stainless steel, drop and wear resistant. This mug can be filled with hot or cold drinks, comes with a mug lid and is great for use both indoors and outdoors. It is also a great choice as a business gift for someone else. customers can customize this coffee cup with their own colors and logos.