The Suunto EON Core is made of different materials:

• The case is made of reinforced composite
• The bezel is made of composite
• The glass is a mineral glass   
• The buttons are made of stainless steel  
• The strap is made of elastomer with stainless steel buckle.

See more about the Suunto EON Core Key Features and Specifications on the product page suunto-eon-core-black