The material is brass on the round plate and titanium for the post. Comes with rubber PT-1 for piercing. Please use the parts with adhesive and use. Cancs with a wire diameter of 1.0 mm or less can be used for cans.Pierced sheetIf you insert it into the post and use it, you can cover your ears from a round plate that touches your ears. * Titanium is a metal that is hard to cause allergies, but rarely can cause metal allergies even in titanium. Please be careful when using it.