Brief Key Chain Skull Punk Can 360&deg; rotation Car Key Ring Birthday Christmas Gift (Black) Zinc, magnesium, copper, aluminum mixed material, high temperature 420-430 degrees Celsius, constant temperature die casting High strength Alloy. It is resistant to corrosion, durable and will last for a long time. Not having to use a quarter or endure the pain of using a thumbnail to put on a key is really handy too. you have grouped your keys on the small rings ( one ring for truck, one for house, one for work, etc. ) If you want to add or remove a ring it is super easy, without breaking your fingernails. Plus it looks pretty cool.