Cowhide leather with comfort lining.Nickel free metal hardware.Interchangeable 1.5″ O-Ring can be replaced with other O-Rings Lockable buckle closure with 24″ leather strap. Ingredients:70% cowhide leather, 30% nickel free metal Includes: 1 Interchangeable O-gag 1.5″ (3.81cm), Lockable with 24″ (60.96cm) leather strap